<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019c766a-a785-79bc-99bb-2ae7cfb8b811,g:1d0c8ab3-7eb0-4bbf-b29b-fcde47f69c59-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://robinhood.com/role/COVER" xlink:type="simple" xlink:href="hood-20251231.xsd#COVER"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/COVER" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitiesTable_019c766a-a9dd-7e3a-a647-f4f268276bcf" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntitiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_EntitiesTable_019c766a-a9dd-7e3a-a647-f4f268276bcf" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019c766a-a9dd-7b18-8fb5-d53faf75a194" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_019c766a-a9dd-7e3a-a647-f4f268276bcf" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019c766a-a9dd-7b18-8fb5-d53faf75a194" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019c766a-a9dd-7b18-8fb5-d53faf75a194_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019c766a-a9dd-7b18-8fb5-d53faf75a194" xlink:to="loc_us-gaap_ClassOfStockDomain_019c766a-a9dd-7b18-8fb5-d53faf75a194_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019c766a-a9dd-70c3-b32f-65c138705cff" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019c766a-a9dd-7b18-8fb5-d53faf75a194" xlink:to="loc_us-gaap_ClassOfStockDomain_019c766a-a9dd-70c3-b32f-65c138705cff" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_019c766a-a9dd-7552-a9a2-b88b17110f2d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonClassAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019c766a-a9dd-70c3-b32f-65c138705cff" xlink:to="loc_us-gaap_CommonClassAMember_019c766a-a9dd-7552-a9a2-b88b17110f2d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassBMember_019c766a-a9dd-7d77-b52b-800fa1df3fa8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonClassBMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019c766a-a9dd-70c3-b32f-65c138705cff" xlink:to="loc_us-gaap_CommonClassBMember_019c766a-a9dd-7d77-b52b-800fa1df3fa8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_019c766a-a9dd-7048-acd4-41e50d35b942" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentType"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_DocumentType_019c766a-a9dd-7048-acd4-41e50d35b942" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentAnnualReport_019c766a-a9dd-72b0-91f2-f3fbf0eb2e21" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentAnnualReport"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_DocumentAnnualReport_019c766a-a9dd-72b0-91f2-f3fbf0eb2e21" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_019c766a-a9dd-7063-a565-b83b614210ee" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentPeriodEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_DocumentPeriodEndDate_019c766a-a9dd-7063-a565-b83b614210ee" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CurrentFiscalYearEndDate_019c766a-a9dd-75b1-a18d-0981637ac14f" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_CurrentFiscalYearEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_CurrentFiscalYearEndDate_019c766a-a9dd-75b1-a18d-0981637ac14f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentTransitionReport_019c766a-a9dd-705c-8e12-ea5f0a670806" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentTransitionReport"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_DocumentTransitionReport_019c766a-a9dd-705c-8e12-ea5f0a670806" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_019c766a-a9dd-73a1-b768-04356d1183f5" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityFileNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_EntityFileNumber_019c766a-a9dd-73a1-b768-04356d1183f5" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_019c766a-a9dd-7d37-9537-068ad1b99cca" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityRegistrantName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_EntityRegistrantName_019c766a-a9dd-7d37-9537-068ad1b99cca" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_019c766a-a9dd-763b-9a3b-6b95d862a3eb" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_EntityIncorporationStateCountryCode_019c766a-a9dd-763b-9a3b-6b95d862a3eb" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_019c766a-a9dd-78ef-ad37-57a6355f7cc1" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_EntityTaxIdentificationNumber_019c766a-a9dd-78ef-ad37-57a6355f7cc1" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_019c766a-a9dd-7953-a5e1-6b332dedccc2" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressAddressLine1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_EntityAddressAddressLine1_019c766a-a9dd-7953-a5e1-6b332dedccc2" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_019c766a-a9dd-7b9d-b89e-d2b9b55362cc" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressCityOrTown"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_EntityAddressCityOrTown_019c766a-a9dd-7b9d-b89e-d2b9b55362cc" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_019c766a-a9dd-78af-b54b-f84d72febdda" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressStateOrProvince"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_EntityAddressStateOrProvince_019c766a-a9dd-78af-b54b-f84d72febdda" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_019c766a-a9dd-72df-b508-90fda3495edf" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressPostalZipCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_EntityAddressPostalZipCode_019c766a-a9dd-72df-b508-90fda3495edf" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_019c766a-a9dd-778f-ba3c-1b9a33193254" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_CityAreaCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_CityAreaCode_019c766a-a9dd-778f-ba3c-1b9a33193254" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_019c766a-a9dd-7a58-98a2-c1725e1c662b" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_LocalPhoneNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_LocalPhoneNumber_019c766a-a9dd-7a58-98a2-c1725e1c662b" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_019c766a-a9dd-7aa3-a73f-3e89ee2f5a07" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_Security12bTitle"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_Security12bTitle_019c766a-a9dd-7aa3-a73f-3e89ee2f5a07" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_019c766a-a9dd-717a-8f7c-1c1b4141af40" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_TradingSymbol"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_TradingSymbol_019c766a-a9dd-717a-8f7c-1c1b4141af40" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_019c766a-a9dd-7407-af36-53ec252f8210" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_SecurityExchangeName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_SecurityExchangeName_019c766a-a9dd-7407-af36-53ec252f8210" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityWellKnownSeasonedIssuer_019c766a-a9dd-71d7-9b1d-255e58cbb835" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityWellKnownSeasonedIssuer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_EntityWellKnownSeasonedIssuer_019c766a-a9dd-71d7-9b1d-255e58cbb835" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityVoluntaryFilers_019c766a-a9dd-7486-804c-02321c41535f" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityVoluntaryFilers"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_EntityVoluntaryFilers_019c766a-a9dd-7486-804c-02321c41535f" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCurrentReportingStatus_019c766a-a9dd-7422-85d7-17f984f153c4" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityCurrentReportingStatus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_EntityCurrentReportingStatus_019c766a-a9dd-7422-85d7-17f984f153c4" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInteractiveDataCurrent_019c766a-a9dd-700a-8b70-de1753a1a88f" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityInteractiveDataCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_EntityInteractiveDataCurrent_019c766a-a9dd-700a-8b70-de1753a1a88f" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFilerCategory_019c766a-a9dd-7df0-8b06-59dd68f2fb7f" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityFilerCategory"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_EntityFilerCategory_019c766a-a9dd-7df0-8b06-59dd68f2fb7f" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitySmallBusiness_019c766a-a9dd-77e4-8382-54e93276a0ed" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntitySmallBusiness"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_EntitySmallBusiness_019c766a-a9dd-77e4-8382-54e93276a0ed" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_019c766a-a9dd-78a5-991b-0c8a0766fc30" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_EntityEmergingGrowthCompany_019c766a-a9dd-78a5-991b-0c8a0766fc30" xlink:type="arc" order="24"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_IcfrAuditorAttestationFlag_019c766a-a9dd-7953-8af2-6fb517974bff" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_IcfrAuditorAttestationFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_IcfrAuditorAttestationFlag_019c766a-a9dd-7953-8af2-6fb517974bff" xlink:type="arc" order="25"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFinStmtErrorCorrectionFlag_019c766a-a9dd-76cf-8446-3b8eb4add3f4" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentFinStmtErrorCorrectionFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_DocumentFinStmtErrorCorrectionFlag_019c766a-a9dd-76cf-8446-3b8eb4add3f4" xlink:type="arc" order="26"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityShellCompany_019c766a-a9dd-712e-8e86-7aa75663d14a" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityShellCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_EntityShellCompany_019c766a-a9dd-712e-8e86-7aa75663d14a" xlink:type="arc" order="27"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityPublicFloat_019c766a-a9dd-717d-90de-dffd557bd4a4" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityPublicFloat"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_EntityPublicFloat_019c766a-a9dd-717d-90de-dffd557bd4a4" xlink:type="arc" order="28"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCommonStockSharesOutstanding_019c766a-a9dd-74f0-b34e-db92db51d2aa" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityCommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_EntityCommonStockSharesOutstanding_019c766a-a9dd-74f0-b34e-db92db51d2aa" xlink:type="arc" order="29"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentsIncorporatedByReferenceTextBlock_019c766a-a9dd-7e65-91aa-e52e720e9b9c" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentsIncorporatedByReferenceTextBlock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_DocumentsIncorporatedByReferenceTextBlock_019c766a-a9dd-7e65-91aa-e52e720e9b9c" xlink:type="arc" order="30"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_019c766a-a9dd-7fae-86de-dd8223f426d0" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityCentralIndexKey"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_EntityCentralIndexKey_019c766a-a9dd-7fae-86de-dd8223f426d0" xlink:type="arc" order="31"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_019c766a-a9dd-7828-a360-d20f25bbd569" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_AmendmentFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_AmendmentFlag_019c766a-a9dd-7828-a360-d20f25bbd569" xlink:type="arc" order="32"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalYearFocus_019c766a-a9dd-72b9-9be0-975fe54f82c4" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentFiscalYearFocus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_DocumentFiscalYearFocus_019c766a-a9dd-72b9-9be0-975fe54f82c4" xlink:type="arc" order="33"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalPeriodFocus_019c766a-a9dd-74a8-9907-454a25d3ca86" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentFiscalPeriodFocus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019c766a-a9dd-74da-8a45-c53681e43817" xlink:to="loc_dei_DocumentFiscalPeriodFocus_019c766a-a9dd-74a8-9907-454a25d3ca86" xlink:type="arc" order="34"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/CONSOLIDATEDBALANCESHEETS" xlink:type="simple" xlink:href="hood-20251231.xsd#CONSOLIDATEDBALANCESHEETS"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/CONSOLIDATEDBALANCESHEETS" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019c766a-a9dd-7da3-ab69-cc7b8c56fbd6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019c766a-a9dd-78cf-a69f-142292d1f6fe" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019c766a-a9dd-7da3-ab69-cc7b8c56fbd6" xlink:to="loc_us-gaap_StatementTable_019c766a-a9dd-78cf-a69f-142292d1f6fe" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019c766a-a9dd-70ee-ab3f-1be7205c976e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019c766a-a9dd-78cf-a69f-142292d1f6fe" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019c766a-a9dd-70ee-ab3f-1be7205c976e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019c766a-a9dd-70ee-ab3f-1be7205c976e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019c766a-a9dd-70ee-ab3f-1be7205c976e" xlink:to="loc_us-gaap_ClassOfStockDomain_019c766a-a9dd-70ee-ab3f-1be7205c976e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019c766a-a9dd-7efa-a383-a54c374e7993" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019c766a-a9dd-70ee-ab3f-1be7205c976e" xlink:to="loc_us-gaap_ClassOfStockDomain_019c766a-a9dd-7efa-a383-a54c374e7993" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_019c766a-a9dd-7190-a50c-f487e691d619" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonClassAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019c766a-a9dd-7efa-a383-a54c374e7993" xlink:to="loc_us-gaap_CommonClassAMember_019c766a-a9dd-7190-a50c-f487e691d619" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassBMember_019c766a-a9dd-7e31-ba06-227388efdd01" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonClassBMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019c766a-a9dd-7efa-a383-a54c374e7993" xlink:to="loc_us-gaap_CommonClassBMember_019c766a-a9dd-7e31-ba06-227388efdd01" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassCMember_019c766a-a9dd-71ff-a2a1-55ae49b14762" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonClassCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019c766a-a9dd-7efa-a383-a54c374e7993" xlink:to="loc_us-gaap_CommonClassCMember_019c766a-a9dd-71ff-a2a1-55ae49b14762" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract_019c766a-a9dd-77c0-b99c-29325888e002" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019c766a-a9dd-7da3-ab69-cc7b8c56fbd6" xlink:to="loc_us-gaap_AssetsAbstract_019c766a-a9dd-77c0-b99c-29325888e002" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrentAbstract_019c766a-a9dd-72ef-a4e7-46f6334a82fb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsCurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019c766a-a9dd-77c0-b99c-29325888e002" xlink:to="loc_us-gaap_AssetsCurrentAbstract_019c766a-a9dd-72ef-a4e7-46f6334a82fb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019c766a-a9dd-70cb-b922-143c7d0b0808" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019c766a-a9dd-72ef-a4e7-46f6334a82fb" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019c766a-a9dd-70cb-b922-143c7d0b0808" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndSecuritiesSegregatedUnderFederalAndOtherRegulations_019c766a-a9dd-7ade-a145-87818e630bf0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashAndSecuritiesSegregatedUnderFederalAndOtherRegulations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019c766a-a9dd-72ef-a4e7-46f6334a82fb" xlink:to="loc_us-gaap_CashAndSecuritiesSegregatedUnderFederalAndOtherRegulations_019c766a-a9dd-7ade-a145-87818e630bf0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivablesFromBrokersDealersAndClearingOrganizations_019c766a-a9dd-7537-9ee7-01e542252cd7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReceivablesFromBrokersDealersAndClearingOrganizations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019c766a-a9dd-72ef-a4e7-46f6334a82fb" xlink:to="loc_us-gaap_ReceivablesFromBrokersDealersAndClearingOrganizations_019c766a-a9dd-7537-9ee7-01e542252cd7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerReceivableAfterAllowanceForCreditLossCurrent_019c766a-a9dd-7485-9291-e3594813bdb0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContractWithCustomerReceivableAfterAllowanceForCreditLossCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019c766a-a9dd-72ef-a4e7-46f6334a82fb" xlink:to="loc_us-gaap_ContractWithCustomerReceivableAfterAllowanceForCreditLossCurrent_019c766a-a9dd-7485-9291-e3594813bdb0" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuritiesBorrowed_019c766a-a9dd-7707-92ea-466723c6bad8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SecuritiesBorrowed"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019c766a-a9dd-72ef-a4e7-46f6334a82fb" xlink:to="loc_us-gaap_SecuritiesBorrowed_019c766a-a9dd-7707-92ea-466723c6bad8" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepositsWithClearingOrganizationsAndOthersSecurities_019c766a-a9dd-7696-b47e-815b468e741e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DepositsWithClearingOrganizationsAndOthersSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019c766a-a9dd-72ef-a4e7-46f6334a82fb" xlink:to="loc_us-gaap_DepositsWithClearingOrganizationsAndOthersSecurities_019c766a-a9dd-7696-b47e-815b468e741e" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_UserHeldFractionalSharesAmount_019c766a-a9dd-7ed7-9504-421a6d26d8f3" xlink:href="hood-20251231.xsd#hood_UserHeldFractionalSharesAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019c766a-a9dd-72ef-a4e7-46f6334a82fb" xlink:to="loc_hood_UserHeldFractionalSharesAmount_019c766a-a9dd-7ed7-9504-421a6d26d8f3" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLossCurrent_019c766a-a9dd-7ee1-8b8e-8dc85f22f620" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLossCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019c766a-a9dd-72ef-a4e7-46f6334a82fb" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLossCurrent_019c766a-a9dd-7ee1-8b8e-8dc85f22f620" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredCostsCurrent_019c766a-a9dd-7c16-8daf-a08cd5d7805e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredCostsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019c766a-a9dd-72ef-a4e7-46f6334a82fb" xlink:to="loc_us-gaap_DeferredCostsCurrent_019c766a-a9dd-7c16-8daf-a08cd5d7805e" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsCurrent_019c766a-a9dd-7837-a9fa-7e1da0e3ca56" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherAssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019c766a-a9dd-72ef-a4e7-46f6334a82fb" xlink:to="loc_us-gaap_OtherAssetsCurrent_019c766a-a9dd-7837-a9fa-7e1da0e3ca56" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrent_019c766a-a9dd-76ef-92c5-54e2849d9634" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_019c766a-a9dd-72ef-a4e7-46f6334a82fb" xlink:to="loc_us-gaap_AssetsCurrent_019c766a-a9dd-76ef-92c5-54e2849d9634" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_019c766a-a9dd-7bff-8ca5-a1b960344f85" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019c766a-a9dd-77c0-b99c-29325888e002" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_019c766a-a9dd-7bff-8ca5-a1b960344f85" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_019c766a-a9dd-75ba-8707-93c3050fa017" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019c766a-a9dd-77c0-b99c-29325888e002" xlink:to="loc_us-gaap_Goodwill_019c766a-a9dd-75ba-8707-93c3050fa017" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_019c766a-a9dd-73e8-ac3c-cdbcc10023f8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019c766a-a9dd-77c0-b99c-29325888e002" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_019c766a-a9dd-73e8-ac3c-cdbcc10023f8" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredCosts_019c766a-a9dd-73a1-8071-5895088359e0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019c766a-a9dd-77c0-b99c-29325888e002" xlink:to="loc_us-gaap_DeferredCosts_019c766a-a9dd-73a1-8071-5895088359e0" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_019c766a-a9dd-7239-b882-b5d60497cbbb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherAssetsNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019c766a-a9dd-77c0-b99c-29325888e002" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_019c766a-a9dd-7239-b882-b5d60497cbbb" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_019c766a-a9dd-7723-a073-2c7cb0dfbfa0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_019c766a-a9dd-77c0-b99c-29325888e002" xlink:to="loc_us-gaap_Assets_019c766a-a9dd-7723-a073-2c7cb0dfbfa0" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019c766a-a9dd-7814-80df-b229de5c6c89" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019c766a-a9dd-7da3-ab69-cc7b8c56fbd6" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019c766a-a9dd-7814-80df-b229de5c6c89" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract_019c766a-a9dd-7de4-ae35-653ba2ab41d0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesCurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019c766a-a9dd-7814-80df-b229de5c6c89" xlink:to="loc_us-gaap_LiabilitiesCurrentAbstract_019c766a-a9dd-7de4-ae35-653ba2ab41d0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent_019c766a-a9dd-7074-ab0a-74f77ac0d268" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019c766a-a9dd-7de4-ae35-653ba2ab41d0" xlink:to="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent_019c766a-a9dd-7074-ab0a-74f77ac0d268" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityCurrent_019c766a-a9dd-7386-be06-575b389bc266" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContractWithCustomerLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019c766a-a9dd-7de4-ae35-653ba2ab41d0" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityCurrent_019c766a-a9dd-7386-be06-575b389bc266" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuritiesLoaned_019c766a-a9dd-71e0-96a2-9e794506406c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SecuritiesLoaned"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019c766a-a9dd-7de4-ae35-653ba2ab41d0" xlink:to="loc_us-gaap_SecuritiesLoaned_019c766a-a9dd-71e0-96a2-9e794506406c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_FractionalSharesRepurchaseObligationAmount_019c766a-a9dd-7ec5-8e0e-d0a684873e9e" xlink:href="hood-20251231.xsd#hood_FractionalSharesRepurchaseObligationAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019c766a-a9dd-7de4-ae35-653ba2ab41d0" xlink:to="loc_hood_FractionalSharesRepurchaseObligationAmount_019c766a-a9dd-7ec5-8e0e-d0a684873e9e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesCurrent_019c766a-a9dd-7334-afd1-17e2b6009af6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019c766a-a9dd-7de4-ae35-653ba2ab41d0" xlink:to="loc_us-gaap_OtherLiabilitiesCurrent_019c766a-a9dd-7334-afd1-17e2b6009af6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrent_019c766a-a9dd-717a-91cf-58df5682b728" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_019c766a-a9dd-7de4-ae35-653ba2ab41d0" xlink:to="loc_us-gaap_LiabilitiesCurrent_019c766a-a9dd-717a-91cf-58df5682b728" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_019c766a-a9dd-7c63-b95b-c41a862256b7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherLiabilitiesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019c766a-a9dd-7814-80df-b229de5c6c89" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_019c766a-a9dd-7c63-b95b-c41a862256b7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_019c766a-a9dd-7ed9-906d-8103b78ef87c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Liabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019c766a-a9dd-7814-80df-b229de5c6c89" xlink:to="loc_us-gaap_Liabilities_019c766a-a9dd-7ed9-906d-8103b78ef87c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingencies_019c766a-a9dd-7f7d-b23a-405432c40ead" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommitmentsAndContingencies"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019c766a-a9dd-7814-80df-b229de5c6c89" xlink:to="loc_us-gaap_CommitmentsAndContingencies_019c766a-a9dd-7f7d-b23a-405432c40ead" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityAbstract_019c766a-a9dd-7f5e-b524-09478863c6b7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019c766a-a9dd-7814-80df-b229de5c6c89" xlink:to="loc_us-gaap_StockholdersEquityAbstract_019c766a-a9dd-7f5e-b524-09478863c6b7" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockValue_019c766a-a9dd-71dc-92f8-bac366daf872" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PreferredStockValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019c766a-a9dd-7f5e-b524-09478863c6b7" xlink:to="loc_us-gaap_PreferredStockValue_019c766a-a9dd-71dc-92f8-bac366daf872" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockValue_019c766a-a9dd-7671-a373-17cd16352a24" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019c766a-a9dd-7f5e-b524-09478863c6b7" xlink:to="loc_us-gaap_CommonStockValue_019c766a-a9dd-7671-a373-17cd16352a24" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapital_019c766a-a9dd-7863-bce0-c0fd6eba2ccb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdditionalPaidInCapital"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019c766a-a9dd-7f5e-b524-09478863c6b7" xlink:to="loc_us-gaap_AdditionalPaidInCapital_019c766a-a9dd-7863-bce0-c0fd6eba2ccb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_019c766a-a9dd-7b53-a2ed-3375bf0c6438" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019c766a-a9dd-7f5e-b524-09478863c6b7" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_019c766a-a9dd-7b53-a2ed-3375bf0c6438" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_019c766a-a9dd-7bcf-9473-883b7c642ef0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019c766a-a9dd-7f5e-b524-09478863c6b7" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_019c766a-a9dd-7bcf-9473-883b7c642ef0" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterest_019c766a-a9dd-744f-973b-6319112e012c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MinorityInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019c766a-a9dd-7f5e-b524-09478863c6b7" xlink:to="loc_us-gaap_MinorityInterest_019c766a-a9dd-744f-973b-6319112e012c" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019c766a-a9dd-7428-b2da-9b0ad05a42a6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_019c766a-a9dd-7f5e-b524-09478863c6b7" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019c766a-a9dd-7428-b2da-9b0ad05a42a6" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_019c766a-a9dd-7c37-8209-9b4f53342b82" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_019c766a-a9dd-7814-80df-b229de5c6c89" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_019c766a-a9dd-7c37-8209-9b4f53342b82" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/CONDENSEDCONSOLIDATEDBALANCESHEETSParenthetical" xlink:type="simple" xlink:href="hood-20251231.xsd#CONDENSEDCONSOLIDATEDBALANCESHEETSParenthetical"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/CONDENSEDCONSOLIDATEDBALANCESHEETSParenthetical" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019c766a-a9dd-7122-92ff-432000a7258c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019c766a-a9dd-73a0-8d81-df1bbaff68a3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019c766a-a9dd-7122-92ff-432000a7258c" xlink:to="loc_us-gaap_StatementTable_019c766a-a9dd-73a0-8d81-df1bbaff68a3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019c766a-a9dd-7155-99e5-ff8f970878c3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019c766a-a9dd-73a0-8d81-df1bbaff68a3" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019c766a-a9dd-7155-99e5-ff8f970878c3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019c766a-a9dd-7155-99e5-ff8f970878c3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019c766a-a9dd-7155-99e5-ff8f970878c3" xlink:to="loc_us-gaap_ClassOfStockDomain_019c766a-a9dd-7155-99e5-ff8f970878c3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019c766a-a9dd-74b1-bfc5-46938b89cd2c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019c766a-a9dd-7155-99e5-ff8f970878c3" xlink:to="loc_us-gaap_ClassOfStockDomain_019c766a-a9dd-74b1-bfc5-46938b89cd2c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_019c766a-a9dd-78c8-b615-284430f93c78" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonClassAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019c766a-a9dd-74b1-bfc5-46938b89cd2c" xlink:to="loc_us-gaap_CommonClassAMember_019c766a-a9dd-78c8-b615-284430f93c78" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassBMember_019c766a-a9dd-74f9-87ab-c98598e2aae5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonClassBMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019c766a-a9dd-74b1-bfc5-46938b89cd2c" xlink:to="loc_us-gaap_CommonClassBMember_019c766a-a9dd-74f9-87ab-c98598e2aae5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassCMember_019c766a-a9dd-7d89-b87c-a8789d527b7a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonClassCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019c766a-a9dd-74b1-bfc5-46938b89cd2c" xlink:to="loc_us-gaap_CommonClassCMember_019c766a-a9dd-7d89-b87c-a8789d527b7a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaidExpenseCurrent_019c766a-a9dd-7a3f-a855-22dd5facecaf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PrepaidExpenseCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019c766a-a9dd-7122-92ff-432000a7258c" xlink:to="loc_us-gaap_PrepaidExpenseCurrent_019c766a-a9dd-7a3f-a855-22dd5facecaf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaidExpenseNoncurrent_019c766a-a9dd-7bea-a8d4-37bdcedb7935" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PrepaidExpenseNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019c766a-a9dd-7122-92ff-432000a7258c" xlink:to="loc_us-gaap_PrepaidExpenseNoncurrent_019c766a-a9dd-7bea-a8d4-37bdcedb7935" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockParOrStatedValuePerShare_019c766a-a9dd-7916-9428-0e065e307ec2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PreferredStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019c766a-a9dd-7122-92ff-432000a7258c" xlink:to="loc_us-gaap_PreferredStockParOrStatedValuePerShare_019c766a-a9dd-7916-9428-0e065e307ec2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesAuthorized_019c766a-a9dd-79e4-bd80-eb619a067586" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PreferredStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019c766a-a9dd-7122-92ff-432000a7258c" xlink:to="loc_us-gaap_PreferredStockSharesAuthorized_019c766a-a9dd-79e4-bd80-eb619a067586" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesIssued_019c766a-a9dd-793e-ad76-acbfaed4dfc6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PreferredStockSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019c766a-a9dd-7122-92ff-432000a7258c" xlink:to="loc_us-gaap_PreferredStockSharesIssued_019c766a-a9dd-793e-ad76-acbfaed4dfc6" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesOutstanding_019c766a-a9dd-7182-8be9-f8135f4352c9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PreferredStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019c766a-a9dd-7122-92ff-432000a7258c" xlink:to="loc_us-gaap_PreferredStockSharesOutstanding_019c766a-a9dd-7182-8be9-f8135f4352c9" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_019c766a-a9dd-738d-b6ca-377ccc9f2d66" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019c766a-a9dd-7122-92ff-432000a7258c" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_019c766a-a9dd-738d-b6ca-377ccc9f2d66" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_019c766a-a9dd-79a3-b1e9-479f09d326ee" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019c766a-a9dd-7122-92ff-432000a7258c" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_019c766a-a9dd-79a3-b1e9-479f09d326ee" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesIssued_019c766a-a9dd-79d3-b562-e1ada3e629b9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019c766a-a9dd-7122-92ff-432000a7258c" xlink:to="loc_us-gaap_CommonStockSharesIssued_019c766a-a9dd-79d3-b562-e1ada3e629b9" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_019c766a-a9dd-7e91-80c5-6515ce2e1f81" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019c766a-a9dd-7122-92ff-432000a7258c" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_019c766a-a9dd-7e91-80c5-6515ce2e1f81" xlink:type="arc" order="9"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/CONSOLIDATEDSTATEMENTSOFOPERATIONS" xlink:type="simple" xlink:href="hood-20251231.xsd#CONSOLIDATEDSTATEMENTSOFOPERATIONS"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/CONSOLIDATEDSTATEMENTSOFOPERATIONS" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019c766a-a9dd-77db-9c12-019fbdc22dac" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019c766a-a9dd-7b52-a9fa-0a5f1ebd1899" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019c766a-a9dd-77db-9c12-019fbdc22dac" xlink:to="loc_us-gaap_StatementTable_019c766a-a9dd-7b52-a9fa-0a5f1ebd1899" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_019c766a-a9dd-7631-91d2-ecc607812bac" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019c766a-a9dd-7b52-a9fa-0a5f1ebd1899" xlink:to="loc_srt_ProductOrServiceAxis_019c766a-a9dd-7631-91d2-ecc607812bac" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019c766a-a9dd-7631-91d2-ecc607812bac_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_019c766a-a9dd-7631-91d2-ecc607812bac" xlink:to="loc_srt_ProductsAndServicesDomain_019c766a-a9dd-7631-91d2-ecc607812bac_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019c766a-a9dd-7568-abb0-4835a863a402" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_019c766a-a9dd-7631-91d2-ecc607812bac" xlink:to="loc_srt_ProductsAndServicesDomain_019c766a-a9dd-7568-abb0-4835a863a402" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_TransactionBasedRevenuesMember_019c766a-a9dd-7060-b483-594648d4923f" xlink:href="hood-20251231.xsd#hood_TransactionBasedRevenuesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019c766a-a9dd-7568-abb0-4835a863a402" xlink:to="loc_hood_TransactionBasedRevenuesMember_019c766a-a9dd-7060-b483-594648d4923f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialServiceOtherMember_019c766a-a9dd-7816-966e-4705542473a2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancialServiceOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019c766a-a9dd-7568-abb0-4835a863a402" xlink:to="loc_us-gaap_FinancialServiceOtherMember_019c766a-a9dd-7816-966e-4705542473a2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenuesAbstract_019c766a-a9dd-72eb-b9ad-1bf9ef38d446" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenuesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019c766a-a9dd-77db-9c12-019fbdc22dac" xlink:to="loc_us-gaap_RevenuesAbstract_019c766a-a9dd-72eb-b9ad-1bf9ef38d446" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019c766a-a9dd-71ee-90c3-d376b14b1218" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_019c766a-a9dd-72eb-b9ad-1bf9ef38d446" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019c766a-a9dd-71ee-90c3-d376b14b1218" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeExpenseNet_019c766a-a9dd-7fc7-8e91-b734d02c6cdb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestIncomeExpenseNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_019c766a-a9dd-72eb-b9ad-1bf9ef38d446" xlink:to="loc_us-gaap_InterestIncomeExpenseNet_019c766a-a9dd-7fc7-8e91-b734d02c6cdb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_019c766a-a9dd-78df-9800-6fcd14afeec5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_019c766a-a9dd-72eb-b9ad-1bf9ef38d446" xlink:to="loc_us-gaap_Revenues_019c766a-a9dd-78df-9800-6fcd14afeec5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpensesAbstract_019c766a-a9dd-7c4d-ba0d-bc3ce486d573" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingExpensesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019c766a-a9dd-77db-9c12-019fbdc22dac" xlink:to="loc_us-gaap_OperatingExpensesAbstract_019c766a-a9dd-7c4d-ba0d-bc3ce486d573" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FloorBrokerageExchangeAndClearanceFees_019c766a-a9dd-7ff8-87f5-93949a4a8930" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FloorBrokerageExchangeAndClearanceFees"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_019c766a-a9dd-7c4d-ba0d-bc3ce486d573" xlink:to="loc_us-gaap_FloorBrokerageExchangeAndClearanceFees_019c766a-a9dd-7ff8-87f5-93949a4a8930" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_TechnologyAndDevelopmentExpense_019c766a-a9dd-7051-a98c-6b86988e8c79" xlink:href="hood-20251231.xsd#hood_TechnologyAndDevelopmentExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_019c766a-a9dd-7c4d-ba0d-bc3ce486d573" xlink:to="loc_hood_TechnologyAndDevelopmentExpense_019c766a-a9dd-7051-a98c-6b86988e8c79" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCostAndExpenseOperating_019c766a-a9dd-7c4d-bb34-f8b674a5663e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherCostAndExpenseOperating"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_019c766a-a9dd-7c4d-ba0d-bc3ce486d573" xlink:to="loc_us-gaap_OtherCostAndExpenseOperating_019c766a-a9dd-7c4d-bb34-f8b674a5663e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProvisionForDoubtfulAccounts_019c766a-a9dd-7e08-9552-d248295dd3f8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProvisionForDoubtfulAccounts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_019c766a-a9dd-7c4d-ba0d-bc3ce486d573" xlink:to="loc_us-gaap_ProvisionForDoubtfulAccounts_019c766a-a9dd-7e08-9552-d248295dd3f8" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MarketingExpense_019c766a-a9dd-7e8a-907e-f6bbf323d7bf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MarketingExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_019c766a-a9dd-7c4d-ba0d-bc3ce486d573" xlink:to="loc_us-gaap_MarketingExpense_019c766a-a9dd-7e8a-907e-f6bbf323d7bf" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_019c766a-a9dd-7cf0-ae7b-ea3671ba799e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_019c766a-a9dd-7c4d-ba0d-bc3ce486d573" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_019c766a-a9dd-7cf0-ae7b-ea3671ba799e" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpenses_019c766a-a9dd-7ef9-a21b-ebfdf767b163" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_019c766a-a9dd-7c4d-ba0d-bc3ce486d573" xlink:to="loc_us-gaap_OperatingExpenses_019c766a-a9dd-7ef9-a21b-ebfdf767b163" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_019c766a-a9dd-747d-94df-c78bda9edf2b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019c766a-a9dd-77db-9c12-019fbdc22dac" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_019c766a-a9dd-747d-94df-c78bda9edf2b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019c766a-a9dd-74d1-b52c-b30fbc5c7e28" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019c766a-a9dd-77db-9c12-019fbdc22dac" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_019c766a-a9dd-74d1-b52c-b30fbc5c7e28" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_019c766a-a9dd-7d93-b748-8d24ab0e01e0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019c766a-a9dd-77db-9c12-019fbdc22dac" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_019c766a-a9dd-7d93-b748-8d24ab0e01e0" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest_019c766a-a9dd-7efc-9f2d-500d14e88bbc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019c766a-a9dd-77db-9c12-019fbdc22dac" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest_019c766a-a9dd-7efc-9f2d-500d14e88bbc" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAttributableToRedeemableNoncontrollingInterest_019c766a-a9dd-7230-9d3d-f87968fea44b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLossAttributableToRedeemableNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019c766a-a9dd-77db-9c12-019fbdc22dac" xlink:to="loc_us-gaap_NetIncomeLossAttributableToRedeemableNoncontrollingInterest_019c766a-a9dd-7230-9d3d-f87968fea44b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019c766a-a9dd-7fb3-9a36-d3230f69355f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019c766a-a9dd-77db-9c12-019fbdc22dac" xlink:to="loc_us-gaap_NetIncomeLoss_019c766a-a9dd-7fb3-9a36-d3230f69355f" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareReconciliationAbstract_019c766a-a9dd-79d4-84b5-ffcecd82d1cf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EarningsPerShareReconciliationAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019c766a-a9dd-77db-9c12-019fbdc22dac" xlink:to="loc_us-gaap_EarningsPerShareReconciliationAbstract_019c766a-a9dd-79d4-84b5-ffcecd82d1cf" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019c766a-a9dd-7013-afeb-660c2b74da12" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareReconciliationAbstract_019c766a-a9dd-79d4-84b5-ffcecd82d1cf" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019c766a-a9dd-7013-afeb-660c2b74da12" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted_019c766a-a9dd-7d84-97a0-410662bd8244" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareReconciliationAbstract_019c766a-a9dd-79d4-84b5-ffcecd82d1cf" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted_019c766a-a9dd-7d84-97a0-410662bd8244" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareAbstract_019c766a-a9dd-76fd-810a-7f8c4e32b65e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EarningsPerShareAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019c766a-a9dd-77db-9c12-019fbdc22dac" xlink:to="loc_us-gaap_EarningsPerShareAbstract_019c766a-a9dd-76fd-810a-7f8c4e32b65e" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_019c766a-a9dd-74f1-81d0-5b95cb1632bd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_019c766a-a9dd-76fd-810a-7f8c4e32b65e" xlink:to="loc_us-gaap_EarningsPerShareBasic_019c766a-a9dd-74f1-81d0-5b95cb1632bd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_019c766a-a9dd-7614-8c50-f5a871c9050f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_019c766a-a9dd-76fd-810a-7f8c4e32b65e" xlink:to="loc_us-gaap_EarningsPerShareDiluted_019c766a-a9dd-7614-8c50-f5a871c9050f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_019c766a-a9dd-774e-aa7b-63bd7383cca6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019c766a-a9dd-77db-9c12-019fbdc22dac" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_019c766a-a9dd-774e-aa7b-63bd7383cca6" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019c766a-a9dd-74fd-884b-2bb7d007746c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_019c766a-a9dd-774e-aa7b-63bd7383cca6" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019c766a-a9dd-74fd-884b-2bb7d007746c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019c766a-a9dd-7a3c-b455-e7663260a76d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_019c766a-a9dd-774e-aa7b-63bd7383cca6" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019c766a-a9dd-7a3c-b455-e7663260a76d" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/CONSOLIDATEDSTATEMENTSOFSTOCKHOLDERSEQUITY" xlink:type="simple" xlink:href="hood-20251231.xsd#CONSOLIDATEDSTATEMENTSOFSTOCKHOLDERSEQUITY"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/CONSOLIDATEDSTATEMENTSOFSTOCKHOLDERSEQUITY" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019c766a-a9dd-73b8-95c5-9d472424598b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019c766a-a9dd-754c-9a32-01ab9bd0fa96" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019c766a-a9dd-73b8-95c5-9d472424598b" xlink:to="loc_us-gaap_StatementTable_019c766a-a9dd-754c-9a32-01ab9bd0fa96" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_019c766a-a9dd-7f61-8653-f1e4b74b1483" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019c766a-a9dd-754c-9a32-01ab9bd0fa96" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_019c766a-a9dd-7f61-8653-f1e4b74b1483" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019c766a-a9dd-7f61-8653-f1e4b74b1483_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019c766a-a9dd-7f61-8653-f1e4b74b1483" xlink:to="loc_us-gaap_EquityComponentDomain_019c766a-a9dd-7f61-8653-f1e4b74b1483_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019c766a-a9dd-7a8b-8f20-8d07a56496ce" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019c766a-a9dd-7f61-8653-f1e4b74b1483" xlink:to="loc_us-gaap_EquityComponentDomain_019c766a-a9dd-7a8b-8f20-8d07a56496ce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_019c766a-a9dd-75fd-b40f-72866d2db09b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019c766a-a9dd-7a8b-8f20-8d07a56496ce" xlink:to="loc_us-gaap_CommonStockMember_019c766a-a9dd-75fd-b40f-72866d2db09b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_019c766a-a9dd-703d-9d6e-d1c3be5ddffc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019c766a-a9dd-7a8b-8f20-8d07a56496ce" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_019c766a-a9dd-703d-9d6e-d1c3be5ddffc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019c766a-a9dd-7938-92a8-891ebf5c7125" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019c766a-a9dd-7a8b-8f20-8d07a56496ce" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019c766a-a9dd-7938-92a8-891ebf5c7125" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_019c766a-a9dd-7498-8c3a-939eea879446" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019c766a-a9dd-7a8b-8f20-8d07a56496ce" xlink:to="loc_us-gaap_RetainedEarningsMember_019c766a-a9dd-7498-8c3a-939eea879446" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestMember_019c766a-a9dd-724d-b183-429d3998363a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019c766a-a9dd-7a8b-8f20-8d07a56496ce" xlink:to="loc_us-gaap_NoncontrollingInterestMember_019c766a-a9dd-724d-b183-429d3998363a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019c766a-a9dd-7015-a191-7e440d966c80" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019c766a-a9dd-73b8-95c5-9d472424598b" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019c766a-a9dd-7015-a191-7e440d966c80" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_019c766a-a9dd-77ef-af7b-06a2dca2fda6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019c766a-a9dd-7015-a191-7e440d966c80" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_019c766a-a9dd-77ef-af7b-06a2dca2fda6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019c766a-a9dd-7b94-aacf-6e450dbaf6dc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019c766a-a9dd-7015-a191-7e440d966c80" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019c766a-a9dd-7b94-aacf-6e450dbaf6dc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019c766a-a9dd-75a5-8ff9-bbbf5fec2c68" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019c766a-a9dd-7015-a191-7e440d966c80" xlink:to="loc_us-gaap_NetIncomeLoss_019c766a-a9dd-75a5-8ff9-bbbf5fec2c68" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_019c766a-a9dd-7c17-a5c8-2c9f0e54d7f6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019c766a-a9dd-7015-a191-7e440d966c80" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_019c766a-a9dd-7c17-a5c8-2c9f0e54d7f6" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_019c766a-a9dd-7bbd-a51d-5b5fc3b5f9c9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019c766a-a9dd-7015-a191-7e440d966c80" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_019c766a-a9dd-7bbd-a51d-5b5fc3b5f9c9" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_StockIssuedDuringPeriodSharesWarrantsExercisesNetOfSharesWithheld_019c766a-a9dd-789e-936b-fae268bfed67" xlink:href="hood-20251231.xsd#hood_StockIssuedDuringPeriodSharesWarrantsExercisesNetOfSharesWithheld"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019c766a-a9dd-7015-a191-7e440d966c80" xlink:to="loc_hood_StockIssuedDuringPeriodSharesWarrantsExercisesNetOfSharesWithheld_019c766a-a9dd-789e-936b-fae268bfed67" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_019c766a-a9dd-7ad9-a73d-92376e4a317b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019c766a-a9dd-7015-a191-7e440d966c80" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_019c766a-a9dd-7ad9-a73d-92376e4a317b" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_019c766a-a9dd-7152-96f0-23cf2f86fa0a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019c766a-a9dd-7015-a191-7e440d966c80" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_019c766a-a9dd-7152-96f0-23cf2f86fa0a" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesAcquisitions_019c766a-a9dd-74ab-93bc-8fad50074d57" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodSharesAcquisitions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019c766a-a9dd-7015-a191-7e440d966c80" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesAcquisitions_019c766a-a9dd-74ab-93bc-8fad50074d57" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures_019c766a-a9dd-748c-87fb-8c3c308aa6a5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019c766a-a9dd-7015-a191-7e440d966c80" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures_019c766a-a9dd-748c-87fb-8c3c308aa6a5" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures_019c766a-a9dd-74d4-af35-66be5c02d930" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019c766a-a9dd-7015-a191-7e440d966c80" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures_019c766a-a9dd-74d4-af35-66be5c02d930" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_019c766a-a9dd-776d-9754-d7dfc74ed7b8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019c766a-a9dd-7015-a191-7e440d966c80" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_019c766a-a9dd-776d-9754-d7dfc74ed7b8" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_019c766a-a9dd-7be5-b1ca-a36b11c2bc1d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019c766a-a9dd-7015-a191-7e440d966c80" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_019c766a-a9dd-7be5-b1ca-a36b11c2bc1d" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019c766a-a9dd-75b7-9a06-35830dce7423" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019c766a-a9dd-7015-a191-7e440d966c80" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_019c766a-a9dd-75b7-9a06-35830dce7423" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_019c766a-a9dd-7d33-8de0-705e361b11d9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019c766a-a9dd-7015-a191-7e440d966c80" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_019c766a-a9dd-7d33-8de0-705e361b11d9" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_StockIssuedDuringPeriodValueCapitalContributionsFromPartner_019c766a-a9dd-7bad-a70e-2233647261c2" xlink:href="hood-20251231.xsd#hood_StockIssuedDuringPeriodValueCapitalContributionsFromPartner"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019c766a-a9dd-7015-a191-7e440d966c80" xlink:to="loc_hood_StockIssuedDuringPeriodValueCapitalContributionsFromPartner_019c766a-a9dd-7bad-a70e-2233647261c2" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_019c766a-a9dd-704a-96d0-5d27beb18a08" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019c766a-a9dd-7f99-8670-396ab10120e7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/DESCRIPTIONOFBUSINESSANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESNarrativeDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#DESCRIPTIONOFBUSINESSANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESNarrativeDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/DESCRIPTIONOFBUSINESSANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsidiarySaleOfStockLineItems_019c766a-a9de-789b-b4f9-da3746f92b6e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsidiarySaleOfStockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable_019c766a-a9dd-7497-b2eb-200936a3bf0b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_019c766a-a9de-789b-b4f9-da3746f92b6e" xlink:to="loc_us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable_019c766a-a9dd-7497-b2eb-200936a3bf0b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_019c766a-a9dd-717a-aff1-f5243e2e7a5f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable_019c766a-a9dd-7497-b2eb-200936a3bf0b" xlink:to="loc_us-gaap_AwardTypeAxis_019c766a-a9dd-717a-aff1-f5243e2e7a5f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-a9dd-717a-aff1-f5243e2e7a5f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_019c766a-a9dd-717a-aff1-f5243e2e7a5f" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-a9dd-717a-aff1-f5243e2e7a5f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-a9dd-7d00-86d8-68c90b00d106" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_019c766a-a9dd-717a-aff1-f5243e2e7a5f" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-a9dd-7d00-86d8-68c90b00d106" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_A2021FoundersAwardCancellationMember_019c766a-a9dd-70c5-8e98-bf77ab413d60" xlink:href="hood-20251231.xsd#hood_A2021FoundersAwardCancellationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-a9dd-7d00-86d8-68c90b00d106" xlink:to="loc_hood_A2021FoundersAwardCancellationMember_019c766a-a9dd-70c5-8e98-bf77ab413d60" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_019c766a-a9dd-7153-8e16-3ee5046a2c6e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-a9dd-7d00-86d8-68c90b00d106" xlink:to="loc_us-gaap_EmployeeStockOptionMember_019c766a-a9dd-7153-8e16-3ee5046a2c6e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_TimeBasedRestrictedStockUnitsRSUsMember_019c766a-a9dd-76af-9509-efa1827e1c16" xlink:href="hood-20251231.xsd#hood_TimeBasedRestrictedStockUnitsRSUsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-a9dd-7d00-86d8-68c90b00d106" xlink:to="loc_hood_TimeBasedRestrictedStockUnitsRSUsMember_019c766a-a9dd-76af-9509-efa1827e1c16" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_MarketBasedRestrictedStockUnitsRSUsMember_019c766a-a9dd-7b75-b73f-dd9e4899c51e" xlink:href="hood-20251231.xsd#hood_MarketBasedRestrictedStockUnitsRSUsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-a9dd-7d00-86d8-68c90b00d106" xlink:to="loc_hood_MarketBasedRestrictedStockUnitsRSUsMember_019c766a-a9dd-7b75-b73f-dd9e4899c51e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionTypeAxis_019c766a-a9dd-7a62-b7a0-0ae15370de45" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TransactionTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable_019c766a-a9dd-7497-b2eb-200936a3bf0b" xlink:to="loc_us-gaap_TransactionTypeAxis_019c766a-a9dd-7a62-b7a0-0ae15370de45" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionDomain_019c766a-a9dd-7a62-b7a0-0ae15370de45_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TransactionTypeAxis_019c766a-a9dd-7a62-b7a0-0ae15370de45" xlink:to="loc_us-gaap_TransactionDomain_019c766a-a9dd-7a62-b7a0-0ae15370de45_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransactionDomain_019c766a-a9dd-732d-8014-8f5c3545beac" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TransactionTypeAxis_019c766a-a9dd-7a62-b7a0-0ae15370de45" xlink:to="loc_us-gaap_TransactionDomain_019c766a-a9dd-732d-8014-8f5c3545beac" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_AgreementOneMember_019c766a-a9dd-78e1-b1d5-0974d67950ab" xlink:href="hood-20251231.xsd#hood_AgreementOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransactionDomain_019c766a-a9dd-732d-8014-8f5c3545beac" xlink:to="loc_hood_AgreementOneMember_019c766a-a9dd-78e1-b1d5-0974d67950ab" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_AgreementTwoMember_019c766a-a9dd-749f-a840-e03b493f7a4d" xlink:href="hood-20251231.xsd#hood_AgreementTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransactionDomain_019c766a-a9dd-732d-8014-8f5c3545beac" xlink:to="loc_hood_AgreementTwoMember_019c766a-a9dd-749f-a840-e03b493f7a4d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_019c766a-a9dd-7ace-911f-cdb417d777b0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable_019c766a-a9dd-7497-b2eb-200936a3bf0b" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_019c766a-a9dd-7ace-911f-cdb417d777b0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_019c766a-a9dd-7ace-911f-cdb417d777b0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_019c766a-a9dd-7ace-911f-cdb417d777b0" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_019c766a-a9dd-7ace-911f-cdb417d777b0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_019c766a-a9de-7270-ba36-e218bfec4f4a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_019c766a-a9dd-7ace-911f-cdb417d777b0" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_019c766a-a9de-7270-ba36-e218bfec4f4a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpenseMember_019c766a-a9de-7143-b77e-b56f4cd4fb11" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GeneralAndAdministrativeExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_019c766a-a9de-7270-ba36-e218bfec4f4a" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpenseMember_019c766a-a9de-7143-b77e-b56f4cd4fb11" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VestingAxis_019c766a-a9de-7cd3-8768-0dcca76e7054" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VestingAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable_019c766a-a9dd-7497-b2eb-200936a3bf0b" xlink:to="loc_us-gaap_VestingAxis_019c766a-a9de-7cd3-8768-0dcca76e7054" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VestingDomain_019c766a-a9de-7cd3-8768-0dcca76e7054_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VestingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VestingAxis_019c766a-a9de-7cd3-8768-0dcca76e7054" xlink:to="loc_us-gaap_VestingDomain_019c766a-a9de-7cd3-8768-0dcca76e7054_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VestingDomain_019c766a-a9de-7c25-8e75-9230b894a285" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VestingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VestingAxis_019c766a-a9de-7cd3-8768-0dcca76e7054" xlink:to="loc_us-gaap_VestingDomain_019c766a-a9de-7c25-8e75-9230b894a285" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationAwardTrancheOneMember_019c766a-a9de-7c08-836c-ffeed21f39b9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationAwardTrancheOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VestingDomain_019c766a-a9de-7c25-8e75-9230b894a285" xlink:to="loc_us-gaap_ShareBasedCompensationAwardTrancheOneMember_019c766a-a9de-7c08-836c-ffeed21f39b9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationAwardTrancheTwoMember_019c766a-a9de-7097-9778-5d92a48a3243" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationAwardTrancheTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VestingDomain_019c766a-a9de-7c25-8e75-9230b894a285" xlink:to="loc_us-gaap_ShareBasedCompensationAwardTrancheTwoMember_019c766a-a9de-7097-9778-5d92a48a3243" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationAwardTrancheThreeMember_019c766a-a9de-7c13-9f71-b9761e14de77" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationAwardTrancheThreeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VestingDomain_019c766a-a9de-7c25-8e75-9230b894a285" xlink:to="loc_us-gaap_ShareBasedCompensationAwardTrancheThreeMember_019c766a-a9de-7c13-9f71-b9761e14de77" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfOperatingSegments_019c766a-a9de-73f3-ae6a-8679abe0804a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NumberOfOperatingSegments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_019c766a-a9de-789b-b4f9-da3746f92b6e" xlink:to="loc_us-gaap_NumberOfOperatingSegments_019c766a-a9de-73f3-ae6a-8679abe0804a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfReportableSegments_019c766a-a9de-702d-a140-d09e631e0115" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NumberOfReportableSegments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_019c766a-a9de-789b-b4f9-da3746f92b6e" xlink:to="loc_us-gaap_NumberOfReportableSegments_019c766a-a9de-702d-a140-d09e631e0115" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedContractCostImpairmentLoss_019c766a-a9de-7123-b21a-8d7e04242c6a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CapitalizedContractCostImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_019c766a-a9de-789b-b4f9-da3746f92b6e" xlink:to="loc_us-gaap_CapitalizedContractCostImpairmentLoss_019c766a-a9de-7123-b21a-8d7e04242c6a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdvertisingExpense_019c766a-a9de-70c0-9bc4-275e482b9a29" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdvertisingExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_019c766a-a9de-789b-b4f9-da3746f92b6e" xlink:to="loc_us-gaap_AdvertisingExpense_019c766a-a9de-70c0-9bc4-275e482b9a29" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_019c766a-a9de-740e-b66e-fe8f7d561925" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_019c766a-a9de-789b-b4f9-da3746f92b6e" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_019c766a-a9de-740e-b66e-fe8f7d561925" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch_019c766a-a9de-77b5-a4bc-8fa0980b5a44" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_019c766a-a9de-789b-b4f9-da3746f92b6e" xlink:to="loc_us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch_019c766a-a9de-77b5-a4bc-8fa0980b5a44" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedContributionPlanCostRecognized_019c766a-a9de-734b-872e-c0ade3077d9d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedContributionPlanCostRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_019c766a-a9de-789b-b4f9-da3746f92b6e" xlink:to="loc_us-gaap_DefinedContributionPlanCostRecognized_019c766a-a9de-734b-872e-c0ade3077d9d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpense_019c766a-a9de-7530-9e59-e1421a6f955f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ResearchAndDevelopmentExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_019c766a-a9de-789b-b4f9-da3746f92b6e" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpense_019c766a-a9de-7530-9e59-e1421a6f955f" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_019c766a-a9de-7ca2-be86-2de5519ec670" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_019c766a-a9de-789b-b4f9-da3746f92b6e" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_019c766a-a9de-7ca2-be86-2de5519ec670" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1_019c766a-a9de-753b-ac7f-7fbf728b75fc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_019c766a-a9de-789b-b4f9-da3746f92b6e" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1_019c766a-a9de-753b-ac7f-7fbf728b75fc" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashCurrent_019c766a-a9de-7340-b6ce-85d9ba809112" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestrictedCashCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_019c766a-a9de-789b-b4f9-da3746f92b6e" xlink:to="loc_us-gaap_RestrictedCashCurrent_019c766a-a9de-7340-b6ce-85d9ba809112" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashNoncurrent_019c766a-a9de-7f5a-84d0-65fb6dee19d9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestrictedCashNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_019c766a-a9de-789b-b4f9-da3746f92b6e" xlink:to="loc_us-gaap_RestrictedCashNoncurrent_019c766a-a9de-7f5a-84d0-65fb6dee19d9" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_SecuritiesLendingAgreementNumberOfFinancialInstitutionCounterparties_019c766a-a9de-7149-9568-d11e1ddb288d" xlink:href="hood-20251231.xsd#hood_SecuritiesLendingAgreementNumberOfFinancialInstitutionCounterparties"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_019c766a-a9de-789b-b4f9-da3746f92b6e" xlink:to="loc_hood_SecuritiesLendingAgreementNumberOfFinancialInstitutionCounterparties_019c766a-a9de-7149-9568-d11e1ddb288d" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_SecuritiesLendingAgreementNumberOfAgreements_019c766a-a9de-7bac-9359-91b1b1aad6fc" xlink:href="hood-20251231.xsd#hood_SecuritiesLendingAgreementNumberOfAgreements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_019c766a-a9de-789b-b4f9-da3746f92b6e" xlink:to="loc_hood_SecuritiesLendingAgreementNumberOfAgreements_019c766a-a9de-7bac-9359-91b1b1aad6fc" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_ContractualObligationContractualTerm_019c766a-a9de-76ba-a21c-23118193b697" xlink:href="hood-20251231.xsd#hood_ContractualObligationContractualTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_019c766a-a9de-789b-b4f9-da3746f92b6e" xlink:to="loc_hood_ContractualObligationContractualTerm_019c766a-a9de-76ba-a21c-23118193b697" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractualObligation_019c766a-a9de-7e84-8a84-c27fe67c60f6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContractualObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_019c766a-a9de-789b-b4f9-da3746f92b6e" xlink:to="loc_us-gaap_ContractualObligation_019c766a-a9de-7e84-8a84-c27fe67c60f6" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_SecuritiesLendingAgreementFixedTermNumberOfAgreements_019c766a-a9de-7010-aab2-bd7d741820d1" xlink:href="hood-20251231.xsd#hood_SecuritiesLendingAgreementFixedTermNumberOfAgreements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_019c766a-a9de-789b-b4f9-da3746f92b6e" xlink:to="loc_hood_SecuritiesLendingAgreementFixedTermNumberOfAgreements_019c766a-a9de-7010-aab2-bd7d741820d1" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_SecuritiesLendingAgreementFixedTermNumberOfCounterparties_019c766a-a9de-7e0d-9411-0402e0c5e244" xlink:href="hood-20251231.xsd#hood_SecuritiesLendingAgreementFixedTermNumberOfCounterparties"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_019c766a-a9de-789b-b4f9-da3746f92b6e" xlink:to="loc_hood_SecuritiesLendingAgreementFixedTermNumberOfCounterparties_019c766a-a9de-7e0d-9411-0402e0c5e244" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_ShortTermSettlementPeriod_019c766a-a9de-79e6-9001-2b01ebc6502f" xlink:href="hood-20251231.xsd#hood_ShortTermSettlementPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_019c766a-a9de-789b-b4f9-da3746f92b6e" xlink:to="loc_hood_ShortTermSettlementPeriod_019c766a-a9de-79e6-9001-2b01ebc6502f" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNoncurrentThresholdPeriodPastDueWriteoff_019c766a-a9de-74d1-9134-c15ab083bd91" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsReceivableNoncurrentThresholdPeriodPastDueWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_019c766a-a9de-789b-b4f9-da3746f92b6e" xlink:to="loc_us-gaap_AccountsReceivableNoncurrentThresholdPeriodPastDueWriteoff_019c766a-a9de-74d1-9134-c15ab083bd91" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerAssetThresholdPeriodPastDueWriteoff_019c766a-a9de-7bbc-9e6a-685db3d32199" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContractWithCustomerAssetThresholdPeriodPastDueWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_019c766a-a9de-789b-b4f9-da3746f92b6e" xlink:to="loc_us-gaap_ContractWithCustomerAssetThresholdPeriodPastDueWriteoff_019c766a-a9de-7bbc-9e6a-685db3d32199" xlink:type="arc" order="20"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/DESCRIPTIONOFBUSINESSANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESScheduleOfConcentrationOfCreditRiskDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#DESCRIPTIONOFBUSINESSANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESScheduleOfConcentrationOfCreditRiskDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/DESCRIPTIONOFBUSINESSANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESScheduleOfConcentrationOfCreditRiskDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskLineItems_019c766a-a9de-7c62-8850-38c6051aef5e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTable_019c766a-a9de-7528-b4ad-3bcbade74de1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_019c766a-a9de-7c62-8850-38c6051aef5e" xlink:to="loc_us-gaap_ConcentrationRiskTable_019c766a-a9de-7528-b4ad-3bcbade74de1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_019c766a-a9de-7e6e-92ef-7a301a11b5e3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_019c766a-a9de-7528-b4ad-3bcbade74de1" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_019c766a-a9de-7e6e-92ef-7a301a11b5e3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_019c766a-a9de-7e6e-92ef-7a301a11b5e3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_019c766a-a9de-7e6e-92ef-7a301a11b5e3" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_019c766a-a9de-7e6e-92ef-7a301a11b5e3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_019c766a-a9de-72df-892f-374f5a54e9da" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_019c766a-a9de-7e6e-92ef-7a301a11b5e3" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_019c766a-a9de-72df-892f-374f5a54e9da" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_019c766a-a9de-7e3f-9614-2faa14d36ae0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CustomerConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_019c766a-a9de-72df-892f-374f5a54e9da" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_019c766a-a9de-7e3f-9614-2faa14d36ae0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019c766a-a9de-78ba-9e62-3e9518780f44" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_019c766a-a9de-7528-b4ad-3bcbade74de1" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019c766a-a9de-78ba-9e62-3e9518780f44" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019c766a-a9de-78ba-9e62-3e9518780f44_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019c766a-a9de-78ba-9e62-3e9518780f44" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019c766a-a9de-78ba-9e62-3e9518780f44_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019c766a-a9de-73f7-a1a6-ab5ee1f6728c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_019c766a-a9de-78ba-9e62-3e9518780f44" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019c766a-a9de-73f7-a1a6-ab5ee1f6728c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesRevenueNetMember_019c766a-a9de-79fb-b68b-33b171b9e6d4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SalesRevenueNetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_019c766a-a9de-73f7-a1a6-ab5ee1f6728c" xlink:to="loc_us-gaap_SalesRevenueNetMember_019c766a-a9de-79fb-b68b-33b171b9e6d4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_019c766a-a9de-7ea4-a659-5ad694a4c5b9" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_019c766a-a9de-7528-b4ad-3bcbade74de1" xlink:to="loc_srt_MajorCustomersAxis_019c766a-a9de-7ea4-a659-5ad694a4c5b9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_019c766a-a9de-7ea4-a659-5ad694a4c5b9_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_019c766a-a9de-7ea4-a659-5ad694a4c5b9" xlink:to="loc_srt_NameOfMajorCustomerDomain_019c766a-a9de-7ea4-a659-5ad694a4c5b9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_019c766a-a9de-773d-a39c-122414fc693f" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_019c766a-a9de-7ea4-a659-5ad694a4c5b9" xlink:to="loc_srt_NameOfMajorCustomerDomain_019c766a-a9de-773d-a39c-122414fc693f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_TotalAsPercentageOfTotalRevenueMember_019c766a-a9de-7c48-ae6f-32334a257644" xlink:href="hood-20251231.xsd#hood_TotalAsPercentageOfTotalRevenueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_019c766a-a9de-773d-a39c-122414fc693f" xlink:to="loc_hood_TotalAsPercentageOfTotalRevenueMember_019c766a-a9de-7c48-ae6f-32334a257644" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_CitadelSecuritiesLLCMember_019c766a-a9de-7401-9fec-d2c4c79e45b1" xlink:href="hood-20251231.xsd#hood_CitadelSecuritiesLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hood_TotalAsPercentageOfTotalRevenueMember_019c766a-a9de-7c48-ae6f-32334a257644" xlink:to="loc_hood_CitadelSecuritiesLLCMember_019c766a-a9de-7401-9fec-d2c4c79e45b1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_WintermuteTradingLtdMember_019c766a-a9de-7ce8-8ac7-3da0678f4463" xlink:href="hood-20251231.xsd#hood_WintermuteTradingLtdMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hood_TotalAsPercentageOfTotalRevenueMember_019c766a-a9de-7c48-ae6f-32334a257644" xlink:to="loc_hood_WintermuteTradingLtdMember_019c766a-a9de-7ce8-8ac7-3da0678f4463" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCustomerMember_019c766a-a9de-7a22-b6ce-325a663f1b3a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherCustomerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hood_TotalAsPercentageOfTotalRevenueMember_019c766a-a9de-7c48-ae6f-32334a257644" xlink:to="loc_us-gaap_OtherCustomerMember_019c766a-a9de-7a22-b6ce-325a663f1b3a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_019c766a-a9de-7741-b669-973069a69895" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_019c766a-a9de-7c62-8850-38c6051aef5e" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_019c766a-a9de-7741-b669-973069a69895" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/DESCRIPTIONOFBUSINESSANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESPropertySoftwareandEquipmentDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#DESCRIPTIONOFBUSINESSANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESPropertySoftwareandEquipmentDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/DESCRIPTIONOFBUSINESSANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESPropertySoftwareandEquipmentDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019c766a-a9de-7f72-9b1d-351a891de4ac" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019c766a-a9de-77dd-9d40-40c33c8edcaa" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019c766a-a9de-7f72-9b1d-351a891de4ac" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019c766a-a9de-77dd-9d40-40c33c8edcaa" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019c766a-a9de-7383-b45a-411630495b71" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019c766a-a9de-77dd-9d40-40c33c8edcaa" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019c766a-a9de-7383-b45a-411630495b71" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019c766a-a9de-7383-b45a-411630495b71_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019c766a-a9de-7383-b45a-411630495b71" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019c766a-a9de-7383-b45a-411630495b71_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019c766a-a9de-709e-9ddf-30ad193083fc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019c766a-a9de-7383-b45a-411630495b71" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019c766a-a9de-709e-9ddf-30ad193083fc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComputerEquipmentMember_019c766a-a9de-795a-9ab7-793735f20f70" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ComputerEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019c766a-a9de-709e-9ddf-30ad193083fc" xlink:to="loc_us-gaap_ComputerEquipmentMember_019c766a-a9de-795a-9ab7-793735f20f70" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FurnitureAndFixturesMember_019c766a-a9de-7efa-95d9-35f1ca7d532a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FurnitureAndFixturesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019c766a-a9de-709e-9ddf-30ad193083fc" xlink:to="loc_us-gaap_FurnitureAndFixturesMember_019c766a-a9de-7efa-95d9-35f1ca7d532a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SoftwareDevelopmentMember_019c766a-a9de-7fd7-ae34-803de9a0089c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SoftwareDevelopmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019c766a-a9de-709e-9ddf-30ad193083fc" xlink:to="loc_us-gaap_SoftwareDevelopmentMember_019c766a-a9de-7fd7-ae34-803de9a0089c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_019c766a-a9de-7c5e-8f64-4e04314955a8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019c766a-a9de-7f72-9b1d-351a891de4ac" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_019c766a-a9de-7c5e-8f64-4e04314955a8" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/BUSINESSCOMBINATIONSNarrativeDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#BUSINESSCOMBINATIONSNarrativeDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/BUSINESSCOMBINATIONSNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_019c766a-aa9f-7107-a6f0-569d13e3ba4e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019c766a-aa9f-71ff-ac80-4ba256501575" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019c766a-aa9f-7107-a6f0-569d13e3ba4e" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019c766a-aa9f-71ff-ac80-4ba256501575" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_019c766a-aa9f-7634-851a-d07bc03ad4b2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019c766a-aa9f-71ff-ac80-4ba256501575" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_019c766a-aa9f-7634-851a-d07bc03ad4b2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aa9f-7634-851a-d07bc03ad4b2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019c766a-aa9f-7634-851a-d07bc03ad4b2" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aa9f-7634-851a-d07bc03ad4b2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aa9f-7c95-865b-15bc2930cb32" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019c766a-aa9f-7634-851a-d07bc03ad4b2" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aa9f-7c95-865b-15bc2930cb32" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_TradePMRMember_019c766a-aa9f-716b-a265-ab735999aa32" xlink:href="hood-20251231.xsd#hood_TradePMRMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aa9f-7c95-865b-15bc2930cb32" xlink:to="loc_hood_TradePMRMember_019c766a-aa9f-716b-a265-ab735999aa32" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_BitstampMember_019c766a-aa9f-79fc-a46f-16afada552ac" xlink:href="hood-20251231.xsd#hood_BitstampMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aa9f-7c95-865b-15bc2930cb32" xlink:to="loc_hood_BitstampMember_019c766a-aa9f-79fc-a46f-16afada552ac" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_MIAXdxMember_019c766a-aa9f-7ce4-9a1a-76b9ebd5abbe" xlink:href="hood-20251231.xsd#hood_MIAXdxMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aa9f-7c95-865b-15bc2930cb32" xlink:to="loc_hood_MIAXdxMember_019c766a-aa9f-7ce4-9a1a-76b9ebd5abbe" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_WonderFiMember_019c766a-aa9f-7994-96fb-f21524529a24" xlink:href="hood-20251231.xsd#hood_WonderFiMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aa9f-7c95-865b-15bc2930cb32" xlink:to="loc_hood_WonderFiMember_019c766a-aa9f-7994-96fb-f21524529a24" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019c766a-aa9f-75f1-9ec5-733e97132976" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019c766a-aa9f-71ff-ac80-4ba256501575" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019c766a-aa9f-75f1-9ec5-733e97132976" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019c766a-aa9f-75f1-9ec5-733e97132976_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019c766a-aa9f-75f1-9ec5-733e97132976" xlink:to="loc_us-gaap_ClassOfStockDomain_019c766a-aa9f-75f1-9ec5-733e97132976_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019c766a-aa9f-7cfb-b150-2aefc8278a64" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019c766a-aa9f-75f1-9ec5-733e97132976" xlink:to="loc_us-gaap_ClassOfStockDomain_019c766a-aa9f-7cfb-b150-2aefc8278a64" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_019c766a-aa9f-7e6b-9068-ba358d7c86dc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonClassAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019c766a-aa9f-7cfb-b150-2aefc8278a64" xlink:to="loc_us-gaap_CommonClassAMember_019c766a-aa9f-7e6b-9068-ba358d7c86dc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_019c766a-aa9f-74e2-b614-a6e38932d999" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationConsiderationTransferred1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019c766a-aa9f-7107-a6f0-569d13e3ba4e" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_019c766a-aa9f-74e2-b614-a6e38932d999" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued_019c766a-aa9f-7374-8d7f-3ba4da08db7b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019c766a-aa9f-7107-a6f0-569d13e3ba4e" xlink:to="loc_us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued_019c766a-aa9f-7374-8d7f-3ba4da08db7b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable_019c766a-aa9f-7cc8-b03b-9f7cb4db18c0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019c766a-aa9f-7107-a6f0-569d13e3ba4e" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable_019c766a-aa9f-7cc8-b03b-9f7cb4db18c0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_019c766a-aa9f-7455-ae38-c1fb74074131" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019c766a-aa9f-7107-a6f0-569d13e3ba4e" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_019c766a-aa9f-7455-ae38-c1fb74074131" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_019c766a-aa9f-74a8-9c33-e7842b634b0a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019c766a-aa9f-7107-a6f0-569d13e3ba4e" xlink:to="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_019c766a-aa9f-74a8-9c33-e7842b634b0a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired_019c766a-aa9f-77b7-8949-341a7b5b9278" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019c766a-aa9f-7107-a6f0-569d13e3ba4e" xlink:to="loc_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired_019c766a-aa9f-77b7-8949-341a7b5b9278" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionSharePrice_019c766a-aa9f-7451-9043-e03f1ede42ed" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionSharePrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019c766a-aa9f-7107-a6f0-569d13e3ba4e" xlink:to="loc_us-gaap_BusinessAcquisitionSharePrice_019c766a-aa9f-7451-9043-e03f1ede42ed" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationPriceOfAcquisitionExpected_019c766a-aa9f-7b66-a31c-5263fb6161c1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationPriceOfAcquisitionExpected"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019c766a-aa9f-7107-a6f0-569d13e3ba4e" xlink:to="loc_us-gaap_BusinessCombinationPriceOfAcquisitionExpected_019c766a-aa9f-7b66-a31c-5263fb6161c1" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/BUSINESSCOMBINATIONSScheduleofAcquisitionDateFairValueofConsiderationTransferredDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#BUSINESSCOMBINATIONSScheduleofAcquisitionDateFairValueofConsiderationTransferredDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/BUSINESSCOMBINATIONSScheduleofAcquisitionDateFairValueofConsiderationTransferredDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_019c766a-aa9f-70a0-9f93-6d2b68e3c024" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019c766a-aa9f-74e5-8457-ca4fcf455d85" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019c766a-aa9f-70a0-9f93-6d2b68e3c024" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019c766a-aa9f-74e5-8457-ca4fcf455d85" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_019c766a-aa9f-7f8a-b85b-d7840103136f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_019c766a-aa9f-74e5-8457-ca4fcf455d85" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_019c766a-aa9f-7f8a-b85b-d7840103136f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aa9f-7f8a-b85b-d7840103136f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019c766a-aa9f-7f8a-b85b-d7840103136f" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aa9f-7f8a-b85b-d7840103136f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aa9f-7055-942d-28402d7478e2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019c766a-aa9f-7f8a-b85b-d7840103136f" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aa9f-7055-942d-28402d7478e2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_RobinhoodCreditMember_019c766a-aa9f-7152-a5f5-2ee5ae7078a0" xlink:href="hood-20251231.xsd#hood_RobinhoodCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aa9f-7055-942d-28402d7478e2" xlink:to="loc_hood_RobinhoodCreditMember_019c766a-aa9f-7152-a5f5-2ee5ae7078a0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_TradePMRMember_019c766a-aa9f-7727-be9c-c1a99a2a5da7" xlink:href="hood-20251231.xsd#hood_TradePMRMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aa9f-7055-942d-28402d7478e2" xlink:to="loc_hood_TradePMRMember_019c766a-aa9f-7727-be9c-c1a99a2a5da7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_BitstampMember_019c766a-aa9f-7b95-9493-4b24c260a056" xlink:href="hood-20251231.xsd#hood_BitstampMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aa9f-7055-942d-28402d7478e2" xlink:to="loc_hood_BitstampMember_019c766a-aa9f-7b95-9493-4b24c260a056" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_019c766a-aa9f-7efd-8d0a-8c50e71d07f2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019c766a-aa9f-70a0-9f93-6d2b68e3c024" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_019c766a-aa9f-7efd-8d0a-8c50e71d07f2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_BusinessCombinationRecognizedAssetAcquiredCashAndSecuritiesSegregatedUnderFederalAndOtherRegulations_019c766a-aa9f-7424-ad04-8c6bcff648db" xlink:href="hood-20251231.xsd#hood_BusinessCombinationRecognizedAssetAcquiredCashAndSecuritiesSegregatedUnderFederalAndOtherRegulations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019c766a-aa9f-70a0-9f93-6d2b68e3c024" xlink:to="loc_hood_BusinessCombinationRecognizedAssetAcquiredCashAndSecuritiesSegregatedUnderFederalAndOtherRegulations_019c766a-aa9f-7424-ad04-8c6bcff648db" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables_019c766a-aa9f-77e2-abe8-8ee80f7a37e5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019c766a-aa9f-70a0-9f93-6d2b68e3c024" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables_019c766a-aa9f-77e2-abe8-8ee80f7a37e5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpense_019c766a-aa9f-725c-93c6-572fa5a99d0a" xlink:href="hood-20251231.xsd#hood_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019c766a-aa9f-70a0-9f93-6d2b68e3c024" xlink:to="loc_hood_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpense_019c766a-aa9f-725c-93c6-572fa5a99d0a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther_019c766a-aa9f-7e3a-b105-daef3943a4b7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019c766a-aa9f-70a0-9f93-6d2b68e3c024" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther_019c766a-aa9f-7e3a-b105-daef3943a4b7" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets_019c766a-aa9f-7cbe-974a-a1bd5ec6b9ef" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019c766a-aa9f-70a0-9f93-6d2b68e3c024" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets_019c766a-aa9f-7cbe-974a-a1bd5ec6b9ef" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_019c766a-aa9f-74ba-a6b9-5874064edb99" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019c766a-aa9f-70a0-9f93-6d2b68e3c024" xlink:to="loc_us-gaap_Goodwill_019c766a-aa9f-74ba-a6b9-5874064edb99" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill_019c766a-aa9f-76ca-b68e-dcb6b2b02511" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019c766a-aa9f-70a0-9f93-6d2b68e3c024" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill_019c766a-aa9f-76ca-b68e-dcb6b2b02511" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayableAndAccruedExpenses_019c766a-aa9f-784c-b509-2ce3445ff518" xlink:href="hood-20251231.xsd#hood_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayableAndAccruedExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019c766a-aa9f-70a0-9f93-6d2b68e3c024" xlink:to="loc_hood_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayableAndAccruedExpenses_019c766a-aa9f-784c-b509-2ce3445ff518" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesPayableToUsers_019c766a-aa9f-7eb5-9342-55c9104446a2" xlink:href="hood-20251231.xsd#hood_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesPayableToUsers"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019c766a-aa9f-70a0-9f93-6d2b68e3c024" xlink:to="loc_hood_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesPayableToUsers_019c766a-aa9f-7eb5-9342-55c9104446a2" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesOther_019c766a-aa9f-7dbf-9733-5b9e3b728317" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019c766a-aa9f-70a0-9f93-6d2b68e3c024" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesOther_019c766a-aa9f-7dbf-9733-5b9e3b728317" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilities_019c766a-aa9f-71d4-bae9-9d887a5aef57" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019c766a-aa9f-70a0-9f93-6d2b68e3c024" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilities_019c766a-aa9f-71d4-bae9-9d887a5aef57" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet_019c766a-aa9f-7ddf-8d31-9972d6c9c132" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_019c766a-aa9f-70a0-9f93-6d2b68e3c024" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet_019c766a-aa9f-7ddf-8d31-9972d6c9c132" xlink:type="arc" order="12"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/BUSINESSCOMBINATIONSScheduleofComponentsofIdentifiableIntangibleAssetsAcquiredDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#BUSINESSCOMBINATIONSScheduleofComponentsofIdentifiableIntangibleAssetsAcquiredDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/BUSINESSCOMBINATIONSScheduleofComponentsofIdentifiableIntangibleAssetsAcquiredDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019c766a-aa9f-7d47-82e6-5aae2cf70bff" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_019c766a-aa9f-792b-bfec-f2c0e23e29d7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019c766a-aa9f-7d47-82e6-5aae2cf70bff" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_019c766a-aa9f-792b-bfec-f2c0e23e29d7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_019c766a-aa9f-7fbd-bf41-a57bdeabddef" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_019c766a-aa9f-792b-bfec-f2c0e23e29d7" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_019c766a-aa9f-7fbd-bf41-a57bdeabddef" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aa9f-7fbd-bf41-a57bdeabddef_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019c766a-aa9f-7fbd-bf41-a57bdeabddef" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aa9f-7fbd-bf41-a57bdeabddef_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aa9f-751e-9436-ea169a96e8f5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019c766a-aa9f-7fbd-bf41-a57bdeabddef" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aa9f-751e-9436-ea169a96e8f5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_TradePMRMember_019c766a-aa9f-73d6-bef1-9aa21e05d8cd" xlink:href="hood-20251231.xsd#hood_TradePMRMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aa9f-751e-9436-ea169a96e8f5" xlink:to="loc_hood_TradePMRMember_019c766a-aa9f-73d6-bef1-9aa21e05d8cd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_BitstampMember_019c766a-aa9f-7c8e-b1f0-a63769684af2" xlink:href="hood-20251231.xsd#hood_BitstampMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aa9f-751e-9436-ea169a96e8f5" xlink:to="loc_hood_BitstampMember_019c766a-aa9f-7c8e-b1f0-a63769684af2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019c766a-aa9f-7abb-adc2-e09c926112ab" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_019c766a-aa9f-792b-bfec-f2c0e23e29d7" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019c766a-aa9f-7abb-adc2-e09c926112ab" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019c766a-aa9f-7abb-adc2-e09c926112ab_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019c766a-aa9f-7abb-adc2-e09c926112ab" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019c766a-aa9f-7abb-adc2-e09c926112ab_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019c766a-aa9f-7d2c-91bc-a00c385ca8a7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019c766a-aa9f-7abb-adc2-e09c926112ab" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019c766a-aa9f-7d2c-91bc-a00c385ca8a7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerRelationshipsMember_019c766a-aa9f-7bb6-a7cd-179f34d96219" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CustomerRelationshipsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019c766a-aa9f-7d2c-91bc-a00c385ca8a7" xlink:to="loc_us-gaap_CustomerRelationshipsMember_019c766a-aa9f-7bb6-a7cd-179f34d96219" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DevelopedTechnologyRightsMember_019c766a-aa9f-72d2-90ec-3ba4e3e576cc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DevelopedTechnologyRightsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019c766a-aa9f-7d2c-91bc-a00c385ca8a7" xlink:to="loc_us-gaap_DevelopedTechnologyRightsMember_019c766a-aa9f-72d2-90ec-3ba4e3e576cc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TradeNamesMember_019c766a-aa9f-7044-8cde-f1d9d40333c7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TradeNamesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019c766a-aa9f-7d2c-91bc-a00c385ca8a7" xlink:to="loc_us-gaap_TradeNamesMember_019c766a-aa9f-7044-8cde-f1d9d40333c7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_019c766a-aa9f-7ceb-9520-ebeef8dc5a71" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019c766a-aa9f-7d47-82e6-5aae2cf70bff" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_019c766a-aa9f-7ceb-9520-ebeef8dc5a71" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_019c766a-aa9f-7179-8186-a5a8ef5b2c0a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019c766a-aa9f-7d47-82e6-5aae2cf70bff" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_019c766a-aa9f-7179-8186-a5a8ef5b2c0a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassLineItems_019c766a-aa9f-72c9-a4a8-709b368cbd99" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfIndefiniteLivedIntangibleAssetsTable_019c766a-aa9f-7cd7-914d-3baa5b96d4be" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfIndefiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassLineItems_019c766a-aa9f-72c9-a4a8-709b368cbd99" xlink:to="loc_us-gaap_ScheduleOfIndefiniteLivedIntangibleAssetsTable_019c766a-aa9f-7cd7-914d-3baa5b96d4be" xlink:type="arc" order="2" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_019c766a-aa9f-7d44-b169-524e7407534c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfIndefiniteLivedIntangibleAssetsTable_019c766a-aa9f-7cd7-914d-3baa5b96d4be" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_019c766a-aa9f-7d44-b169-524e7407534c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aa9f-7d44-b169-524e7407534c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aa9f-748c-b060-ea1639ef2e0b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_BitstampMember_019c766a-aa9f-7d2d-8ef7-3370927328bb" xlink:href="hood-20251231.xsd#hood_BitstampMember"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_019c766a-aa9f-77f1-818e-0381b431c468" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfIndefiniteLivedIntangibleAssetsTable_019c766a-aa9f-7cd7-914d-3baa5b96d4be" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_019c766a-aa9f-77f1-818e-0381b431c468" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_019c766a-aa9f-77f1-818e-0381b431c468_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_019c766a-aa9f-77f1-818e-0381b431c468" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_019c766a-aa9f-77f1-818e-0381b431c468_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_019c766a-aa9f-7c30-98a7-e2157ef9e7e1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_019c766a-aa9f-77f1-818e-0381b431c468" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_019c766a-aa9f-7c30-98a7-e2157ef9e7e1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LicenseMember_019c766a-aa9f-775d-a41d-b74e4787616c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LicenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_019c766a-aa9f-7c30-98a7-e2157ef9e7e1" xlink:to="loc_us-gaap_LicenseMember_019c766a-aa9f-775d-a41d-b74e4787616c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherIntangibleAssetsMember_019c766a-aa9f-7d73-b3bb-abc094bfc225" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherIntangibleAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_019c766a-aa9f-7c30-98a7-e2157ef9e7e1" xlink:to="loc_us-gaap_OtherIntangibleAssetsMember_019c766a-aa9f-7d73-b3bb-abc094bfc225" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIndefiniteLivedIntangibleAssets_019c766a-aa9f-7789-b2f3-ada09f7c3ee9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIndefiniteLivedIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassLineItems_019c766a-aa9f-72c9-a4a8-709b368cbd99" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIndefiniteLivedIntangibleAssets_019c766a-aa9f-7789-b2f3-ada09f7c3ee9" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/GOODWILLANDINTANGIBLEASSETSScheduleofComponentsofFiniteLivedIntangibleAssetsDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#GOODWILLANDINTANGIBLEASSETSScheduleofComponentsofFiniteLivedIntangibleAssetsDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/GOODWILLANDINTANGIBLEASSETSScheduleofComponentsofFiniteLivedIntangibleAssetsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019c766a-aa9f-7b56-857a-621351b2e380" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_019c766a-aa9f-78fe-86b0-2b65922a3b78" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019c766a-aa9f-7b56-857a-621351b2e380" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_019c766a-aa9f-78fe-86b0-2b65922a3b78" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019c766a-aa9f-734e-bd04-068a5b55f42b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_019c766a-aa9f-78fe-86b0-2b65922a3b78" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019c766a-aa9f-734e-bd04-068a5b55f42b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019c766a-aa9f-734e-bd04-068a5b55f42b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019c766a-aa9f-734e-bd04-068a5b55f42b" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019c766a-aa9f-734e-bd04-068a5b55f42b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019c766a-aa9f-794e-815d-a108abe9ee0d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_019c766a-aa9f-734e-bd04-068a5b55f42b" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019c766a-aa9f-794e-815d-a108abe9ee0d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DevelopedTechnologyRightsMember_019c766a-aa9f-7001-9c4b-eb33525835f7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DevelopedTechnologyRightsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019c766a-aa9f-794e-815d-a108abe9ee0d" xlink:to="loc_us-gaap_DevelopedTechnologyRightsMember_019c766a-aa9f-7001-9c4b-eb33525835f7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerRelationshipsMember_019c766a-aa9f-7b0b-9592-3d0d752197c2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CustomerRelationshipsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019c766a-aa9f-794e-815d-a108abe9ee0d" xlink:to="loc_us-gaap_CustomerRelationshipsMember_019c766a-aa9f-7b0b-9592-3d0d752197c2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TradeNamesMember_019c766a-aa9f-7335-9a4f-ac983df18abc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TradeNamesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_019c766a-aa9f-794e-815d-a108abe9ee0d" xlink:to="loc_us-gaap_TradeNamesMember_019c766a-aa9f-7335-9a4f-ac983df18abc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_019c766a-aa9f-7051-892e-6172773157f7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019c766a-aa9f-7b56-857a-621351b2e380" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_019c766a-aa9f-7051-892e-6172773157f7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_019c766a-aa9f-730d-9123-4ac31aec245b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019c766a-aa9f-7b56-857a-621351b2e380" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_019c766a-aa9f-730d-9123-4ac31aec245b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_019c766a-aa9f-7bbb-b3fb-60cbdbcd9474" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019c766a-aa9f-7b56-857a-621351b2e380" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_019c766a-aa9f-7bbb-b3fb-60cbdbcd9474" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_019c766a-aa9f-7bff-9fc0-537ee771db3b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_019c766a-aa9f-7b56-857a-621351b2e380" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_019c766a-aa9f-7bff-9fc0-537ee771db3b" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/REVENUESRevenueDisaggregatedbyRevenueSourcesDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#REVENUESRevenueDisaggregatedbyRevenueSourcesDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/REVENUESRevenueDisaggregatedbyRevenueSourcesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_019c766a-aa9f-7cc1-9b0f-746a875fa29c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_019c766a-aa9f-7b7b-9938-af369227626d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019c766a-aa9f-7cc1-9b0f-746a875fa29c" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_019c766a-aa9f-7b7b-9938-af369227626d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_019c766a-aa9f-73ef-94df-df4d1cef35e1" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_019c766a-aa9f-7b7b-9938-af369227626d" xlink:to="loc_srt_ProductOrServiceAxis_019c766a-aa9f-73ef-94df-df4d1cef35e1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019c766a-aa9f-73ef-94df-df4d1cef35e1_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_019c766a-aa9f-73ef-94df-df4d1cef35e1" xlink:to="loc_srt_ProductsAndServicesDomain_019c766a-aa9f-73ef-94df-df4d1cef35e1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019c766a-aa9f-7801-a18e-9f266dd75772" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_019c766a-aa9f-73ef-94df-df4d1cef35e1" xlink:to="loc_srt_ProductsAndServicesDomain_019c766a-aa9f-7801-a18e-9f266dd75772" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_TransactionBasedRevenuesMember_019c766a-aa9f-7b8b-a7fc-9a363bcc4f25" xlink:href="hood-20251231.xsd#hood_TransactionBasedRevenuesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019c766a-aa9f-7801-a18e-9f266dd75772" xlink:to="loc_hood_TransactionBasedRevenuesMember_019c766a-aa9f-7b8b-a7fc-9a363bcc4f25" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_OptionsMember_019c766a-aa9f-769a-aa68-f245d5dc0ad7" xlink:href="hood-20251231.xsd#hood_OptionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hood_TransactionBasedRevenuesMember_019c766a-aa9f-7b8b-a7fc-9a363bcc4f25" xlink:to="loc_hood_OptionsMember_019c766a-aa9f-769a-aa68-f245d5dc0ad7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_CryptocurrenciesMember_019c766a-aa9f-7422-b04b-a7ef3fc1934f" xlink:href="hood-20251231.xsd#hood_CryptocurrenciesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hood_TransactionBasedRevenuesMember_019c766a-aa9f-7b8b-a7fc-9a363bcc4f25" xlink:to="loc_hood_CryptocurrenciesMember_019c766a-aa9f-7422-b04b-a7ef3fc1934f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_EquitiesMember_019c766a-aa9f-723e-a490-147d68d421ff" xlink:href="hood-20251231.xsd#hood_EquitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hood_TransactionBasedRevenuesMember_019c766a-aa9f-7b8b-a7fc-9a363bcc4f25" xlink:to="loc_hood_EquitiesMember_019c766a-aa9f-723e-a490-147d68d421ff" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_OtherTransactionBasedRevenuesMember_019c766a-aa9f-7754-97d0-80bcdf7065f2" xlink:href="hood-20251231.xsd#hood_OtherTransactionBasedRevenuesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hood_TransactionBasedRevenuesMember_019c766a-aa9f-7b8b-a7fc-9a363bcc4f25" xlink:to="loc_hood_OtherTransactionBasedRevenuesMember_019c766a-aa9f-7754-97d0-80bcdf7065f2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_MarginInterestMember_019c766a-aa9f-7fda-a825-de50b3c3ea44" xlink:href="hood-20251231.xsd#hood_MarginInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019c766a-aa9f-7801-a18e-9f266dd75772" xlink:to="loc_hood_MarginInterestMember_019c766a-aa9f-7fda-a825-de50b3c3ea44" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_InterestOnSegregatedCashAndCashEquivalentsSecuritiesAndDepositsMember_019c766a-aa9f-706b-89c3-7d7bc679cab6" xlink:href="hood-20251231.xsd#hood_InterestOnSegregatedCashAndCashEquivalentsSecuritiesAndDepositsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019c766a-aa9f-7801-a18e-9f266dd75772" xlink:to="loc_hood_InterestOnSegregatedCashAndCashEquivalentsSecuritiesAndDepositsMember_019c766a-aa9f-706b-89c3-7d7bc679cab6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_CashSweepMember_019c766a-aa9f-7171-b43a-6b099ef7b80f" xlink:href="hood-20251231.xsd#hood_CashSweepMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019c766a-aa9f-7801-a18e-9f266dd75772" xlink:to="loc_hood_CashSweepMember_019c766a-aa9f-7171-b43a-6b099ef7b80f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_SecuritiesLendingNetMember_019c766a-aa9f-758e-8054-8918d3c162d0" xlink:href="hood-20251231.xsd#hood_SecuritiesLendingNetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019c766a-aa9f-7801-a18e-9f266dd75772" xlink:to="loc_hood_SecuritiesLendingNetMember_019c766a-aa9f-758e-8054-8918d3c162d0" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_InterestOnCorporateCashAndInvestmentsMember_019c766a-aa9f-7c4f-85c0-ebdd7fcab4c8" xlink:href="hood-20251231.xsd#hood_InterestOnCorporateCashAndInvestmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019c766a-aa9f-7801-a18e-9f266dd75772" xlink:to="loc_hood_InterestOnCorporateCashAndInvestmentsMember_019c766a-aa9f-7c4f-85c0-ebdd7fcab4c8" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_CreditCardNetMember_019c766a-aa9f-7946-bf0f-66f865e9445b" xlink:href="hood-20251231.xsd#hood_CreditCardNetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019c766a-aa9f-7801-a18e-9f266dd75772" xlink:to="loc_hood_CreditCardNetMember_019c766a-aa9f-7946-bf0f-66f865e9445b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialServiceOtherMember_019c766a-aa9f-7407-ac14-f71ac667746c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancialServiceOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019c766a-aa9f-7801-a18e-9f266dd75772" xlink:to="loc_us-gaap_FinancialServiceOtherMember_019c766a-aa9f-7407-ac14-f71ac667746c" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_GoldSubscriptionRevenuesMember_019c766a-aa9f-7dd4-a4e7-75356e6eee7b" xlink:href="hood-20251231.xsd#hood_GoldSubscriptionRevenuesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialServiceOtherMember_019c766a-aa9f-7407-ac14-f71ac667746c" xlink:to="loc_hood_GoldSubscriptionRevenuesMember_019c766a-aa9f-7dd4-a4e7-75356e6eee7b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_ProxyRevenuesMember_019c766a-aa9f-765d-8463-947dd3fd205e" xlink:href="hood-20251231.xsd#hood_ProxyRevenuesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialServiceOtherMember_019c766a-aa9f-7407-ac14-f71ac667746c" xlink:to="loc_hood_ProxyRevenuesMember_019c766a-aa9f-765d-8463-947dd3fd205e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_OtherRevenueMember_019c766a-aa9f-7c16-8617-0f335922436b" xlink:href="hood-20251231.xsd#hood_OtherRevenueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialServiceOtherMember_019c766a-aa9f-7407-ac14-f71ac667746c" xlink:to="loc_hood_OtherRevenueMember_019c766a-aa9f-7c16-8617-0f335922436b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019c766a-aa9f-72f6-a4cc-cab12ff1a308" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019c766a-aa9f-7cc1-9b0f-746a875fa29c" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_019c766a-aa9f-72f6-a4cc-cab12ff1a308" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeInterestEarningAsset_019c766a-aa9f-7354-bfdb-4629f8f1d654" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestIncomeInterestEarningAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019c766a-aa9f-7cc1-9b0f-746a875fa29c" xlink:to="loc_us-gaap_InterestIncomeInterestEarningAsset_019c766a-aa9f-7354-bfdb-4629f8f1d654" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseBorrowings_019c766a-aa9f-72e1-b93c-76f798f7f209" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestExpenseBorrowings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019c766a-aa9f-7cc1-9b0f-746a875fa29c" xlink:to="loc_us-gaap_InterestExpenseBorrowings_019c766a-aa9f-72e1-b93c-76f798f7f209" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeExpenseNet_019c766a-aa9f-787a-b33d-5f5785bc2d1e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestIncomeExpenseNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019c766a-aa9f-7cc1-9b0f-746a875fa29c" xlink:to="loc_us-gaap_InterestIncomeExpenseNet_019c766a-aa9f-787a-b33d-5f5785bc2d1e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_019c766a-aa9f-70e8-b978-35a98aaa2724" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019c766a-aa9f-7cc1-9b0f-746a875fa29c" xlink:to="loc_us-gaap_Revenues_019c766a-aa9f-70e8-b978-35a98aaa2724" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/REVENUESInterestRevenueEarnedAndInterestExpensePaidFromSecuritiesLendingDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#REVENUESInterestRevenueEarnedAndInterestExpensePaidFromSecuritiesLendingDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/REVENUESInterestRevenueEarnedAndInterestExpensePaidFromSecuritiesLendingDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_019c766a-aa9f-78be-9e3c-0418c7be42b8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_019c766a-aa9f-75e2-8b8c-7a01b52f2f54" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019c766a-aa9f-78be-9e3c-0418c7be42b8" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_019c766a-aa9f-75e2-8b8c-7a01b52f2f54" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_019c766a-aa9f-71d3-9887-dfcd80bed6f1" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_019c766a-aa9f-75e2-8b8c-7a01b52f2f54" xlink:to="loc_srt_ProductOrServiceAxis_019c766a-aa9f-71d3-9887-dfcd80bed6f1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019c766a-aa9f-71d3-9887-dfcd80bed6f1_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_019c766a-aa9f-71d3-9887-dfcd80bed6f1" xlink:to="loc_srt_ProductsAndServicesDomain_019c766a-aa9f-71d3-9887-dfcd80bed6f1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019c766a-aa9f-7c07-9195-0f907089983e" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_019c766a-aa9f-71d3-9887-dfcd80bed6f1" xlink:to="loc_srt_ProductsAndServicesDomain_019c766a-aa9f-7c07-9195-0f907089983e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_SecuritiesLendingMember_019c766a-aa9f-7b0a-befb-8eea7968e68b" xlink:href="hood-20251231.xsd#hood_SecuritiesLendingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019c766a-aa9f-7c07-9195-0f907089983e" xlink:to="loc_hood_SecuritiesLendingMember_019c766a-aa9f-7b0a-befb-8eea7968e68b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeOperating_019c766a-aa9f-7df0-ba45-8de7f036e4c6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestIncomeOperating"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019c766a-aa9f-78be-9e3c-0418c7be42b8" xlink:to="loc_us-gaap_InterestIncomeOperating_019c766a-aa9f-7df0-ba45-8de7f036e4c6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseOperating_019c766a-aa9f-7926-b347-bebf47e0ff0a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestExpenseOperating"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019c766a-aa9f-78be-9e3c-0418c7be42b8" xlink:to="loc_us-gaap_InterestExpenseOperating_019c766a-aa9f-7926-b347-bebf47e0ff0a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRevenueExpenseNet_019c766a-aa9f-7572-97bf-c975b2161b4b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestRevenueExpenseNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019c766a-aa9f-78be-9e3c-0418c7be42b8" xlink:to="loc_us-gaap_InterestRevenueExpenseNet_019c766a-aa9f-7572-97bf-c975b2161b4b" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/REVENUESNarrativeDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#REVENUESNarrativeDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/REVENUESNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_019c766a-aa9f-748c-b59e-c59678e9fa33" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_019c766a-aa9f-779c-bcc8-a5641803fc05" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019c766a-aa9f-748c-b59e-c59678e9fa33" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_019c766a-aa9f-779c-bcc8-a5641803fc05" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_ContractWithCustomerLiabilityAxis_019c766a-aa9f-77ea-9796-c3726293c8b7" xlink:href="hood-20251231.xsd#hood_ContractWithCustomerLiabilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_019c766a-aa9f-779c-bcc8-a5641803fc05" xlink:to="loc_hood_ContractWithCustomerLiabilityAxis_019c766a-aa9f-77ea-9796-c3726293c8b7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_ContractWithCustomerLiabilityDomain_019c766a-aa9f-77ea-9796-c3726293c8b7_default" xlink:href="hood-20251231.xsd#hood_ContractWithCustomerLiabilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_hood_ContractWithCustomerLiabilityAxis_019c766a-aa9f-77ea-9796-c3726293c8b7" xlink:to="loc_hood_ContractWithCustomerLiabilityDomain_019c766a-aa9f-77ea-9796-c3726293c8b7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_ContractWithCustomerLiabilityDomain_019c766a-aa9f-753a-abed-ced19b44e430" xlink:href="hood-20251231.xsd#hood_ContractWithCustomerLiabilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_hood_ContractWithCustomerLiabilityAxis_019c766a-aa9f-77ea-9796-c3726293c8b7" xlink:to="loc_hood_ContractWithCustomerLiabilityDomain_019c766a-aa9f-753a-abed-ced19b44e430" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_UnearnedRobinhoodGoldAndRobinhoodGoldCardMember_019c766a-aa9f-7145-9213-31d9b94b395e" xlink:href="hood-20251231.xsd#hood_UnearnedRobinhoodGoldAndRobinhoodGoldCardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hood_ContractWithCustomerLiabilityDomain_019c766a-aa9f-753a-abed-ced19b44e430" xlink:to="loc_hood_UnearnedRobinhoodGoldAndRobinhoodGoldCardMember_019c766a-aa9f-7145-9213-31d9b94b395e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_019c766a-aa9f-7cde-9efa-a2a3101bdd91" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_019c766a-aa9f-779c-bcc8-a5641803fc05" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_019c766a-aa9f-7cde-9efa-a2a3101bdd91" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aa9f-7cde-9efa-a2a3101bdd91_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019c766a-aa9f-7cde-9efa-a2a3101bdd91" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aa9f-7cde-9efa-a2a3101bdd91_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aa9f-787b-9e7a-8b7bcfe552d4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019c766a-aa9f-7cde-9efa-a2a3101bdd91" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aa9f-787b-9e7a-8b7bcfe552d4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_TradePMRMember_019c766a-aa9f-7240-9a13-147abb612237" xlink:href="hood-20251231.xsd#hood_TradePMRMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aa9f-787b-9e7a-8b7bcfe552d4" xlink:to="loc_hood_TradePMRMember_019c766a-aa9f-7240-9a13-147abb612237" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiability_019c766a-aa9f-7667-bbac-76afd1d4fae5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContractWithCustomerLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019c766a-aa9f-748c-b59e-c59678e9fa33" xlink:to="loc_us-gaap_ContractWithCustomerLiability_019c766a-aa9f-7667-bbac-76afd1d4fae5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityCurrent_019c766a-aa9f-73e6-9cfe-6cbed8c07b28" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContractWithCustomerLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019c766a-aa9f-748c-b59e-c59678e9fa33" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityCurrent_019c766a-aa9f-73e6-9cfe-6cbed8c07b28" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityNoncurrent_019c766a-aa9f-7d20-a6a2-a6547a20e135" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContractWithCustomerLiabilityNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_019c766a-aa9f-748c-b59e-c59678e9fa33" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityNoncurrent_019c766a-aa9f-7d20-a6a2-a6547a20e135" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/ALLOWANCEFORCREDITLOSSESScheduleofAllowanceforCreditLossesofBrokerageRelatedDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#ALLOWANCEFORCREDITLOSSESScheduleofAllowanceforCreditLossesofBrokerageRelatedDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/ALLOWANCEFORCREDITLOSSESScheduleofAllowanceforCreditLossesofBrokerageRelatedDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019c766a-aa9f-7de2-b77a-fe8a3a40bf45" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019c766a-aa9f-7ff3-b45a-eef60ffa8d38" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019c766a-aa9f-7de2-b77a-fe8a3a40bf45" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019c766a-aa9f-7ff3-b45a-eef60ffa8d38" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_019c766a-aa9f-7d40-9e0d-ecb6c2abb6a4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019c766a-aa9f-7ff3-b45a-eef60ffa8d38" xlink:to="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_019c766a-aa9f-7d40-9e0d-ecb6c2abb6a4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_019c766a-aa9f-7d40-9e0d-ecb6c2abb6a4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_019c766a-aa9f-7d40-9e0d-ecb6c2abb6a4" xlink:to="loc_us-gaap_ReceivableTypeDomain_019c766a-aa9f-7d40-9e0d-ecb6c2abb6a4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_019c766a-aa9f-7b5a-88ed-1efeec8c62a1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_019c766a-aa9f-7d40-9e0d-ecb6c2abb6a4" xlink:to="loc_us-gaap_ReceivableTypeDomain_019c766a-aa9f-7b5a-88ed-1efeec8c62a1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_BrokerageRelatedReceivablesMember_019c766a-aa9f-7d66-9539-fd0deed834f3" xlink:href="hood-20251231.xsd#hood_BrokerageRelatedReceivablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReceivableTypeDomain_019c766a-aa9f-7b5a-88ed-1efeec8c62a1" xlink:to="loc_hood_BrokerageRelatedReceivablesMember_019c766a-aa9f-7d66-9539-fd0deed834f3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward_019c766a-aa9f-761f-bdb6-cfe4ebee3e6c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019c766a-aa9f-7de2-b77a-fe8a3a40bf45" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward_019c766a-aa9f-761f-bdb6-cfe4ebee3e6c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable_019c766a-aa9f-7eae-9935-32076cf7418e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward_019c766a-aa9f-761f-bdb6-cfe4ebee3e6c" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable_019c766a-aa9f-7eae-9935-32076cf7418e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProvisionForDoubtfulAccounts_019c766a-aa9f-7760-9229-0cc169c76a3f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProvisionForDoubtfulAccounts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward_019c766a-aa9f-761f-bdb6-cfe4ebee3e6c" xlink:to="loc_us-gaap_ProvisionForDoubtfulAccounts_019c766a-aa9f-7760-9229-0cc169c76a3f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableWriteOffs_019c766a-aa9f-7133-aebd-fd7bb1cd8d5c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivableWriteOffs"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward_019c766a-aa9f-761f-bdb6-cfe4ebee3e6c" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableWriteOffs_019c766a-aa9f-7133-aebd-fd7bb1cd8d5c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableRecoveries_019c766a-aa9f-7cf0-b901-f223884894ce" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivableRecoveries"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward_019c766a-aa9f-761f-bdb6-cfe4ebee3e6c" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableRecoveries_019c766a-aa9f-7cf0-b901-f223884894ce" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable_019c766a-aa9f-7e58-a91e-83afa569c482" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivable"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/ALLOWANCEFORCREDITLOSSESScheduleofAllowanceforCreditLossesofReceivablesFromUsersDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#ALLOWANCEFORCREDITLOSSESScheduleofAllowanceforCreditLossesofReceivablesFromUsersDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/ALLOWANCEFORCREDITLOSSESScheduleofAllowanceforCreditLossesofReceivablesFromUsersDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019c766a-aa9f-7520-8140-a6a6e1beb5b1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019c766a-aa9f-7697-ba3b-5f837d64a8b2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019c766a-aa9f-7520-8140-a6a6e1beb5b1" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019c766a-aa9f-7697-ba3b-5f837d64a8b2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_019c766a-aa9f-7b3b-86f3-72461fcb5ec0" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019c766a-aa9f-7697-ba3b-5f837d64a8b2" xlink:to="loc_dei_LegalEntityAxis_019c766a-aa9f-7b3b-86f3-72461fcb5ec0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_019c766a-aa9f-7b3b-86f3-72461fcb5ec0_default" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_019c766a-aa9f-7b3b-86f3-72461fcb5ec0" xlink:to="loc_dei_EntityDomain_019c766a-aa9f-7b3b-86f3-72461fcb5ec0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_019c766a-aa9f-72e6-863f-ff60f4c1912e" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_019c766a-aa9f-7b3b-86f3-72461fcb5ec0" xlink:to="loc_dei_EntityDomain_019c766a-aa9f-72e6-863f-ff60f4c1912e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_RobinhoodCreditMember_019c766a-aa9f-7e25-9763-6533b25fc129" xlink:href="hood-20251231.xsd#hood_RobinhoodCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_019c766a-aa9f-72e6-863f-ff60f4c1912e" xlink:to="loc_hood_RobinhoodCreditMember_019c766a-aa9f-7e25-9763-6533b25fc129" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerAssetAllowanceForCreditLossRollForward_019c766a-aa9f-76f9-b8a1-ddf0fac5ead2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContractWithCustomerAssetAllowanceForCreditLossRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019c766a-aa9f-7520-8140-a6a6e1beb5b1" xlink:to="loc_us-gaap_ContractWithCustomerAssetAllowanceForCreditLossRollForward_019c766a-aa9f-76f9-b8a1-ddf0fac5ead2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerReceivableAllowanceForCreditLoss_019c766a-aa9f-7783-b47b-caaa54024339" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContractWithCustomerReceivableAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerAssetAllowanceForCreditLossRollForward_019c766a-aa9f-76f9-b8a1-ddf0fac5ead2" xlink:to="loc_us-gaap_ContractWithCustomerReceivableAllowanceForCreditLoss_019c766a-aa9f-7783-b47b-caaa54024339" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerAssetCreditLossExpense_019c766a-aa9f-7ed0-b4fc-3ef0d732416f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContractWithCustomerAssetCreditLossExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerAssetAllowanceForCreditLossRollForward_019c766a-aa9f-76f9-b8a1-ddf0fac5ead2" xlink:to="loc_us-gaap_ContractWithCustomerAssetCreditLossExpense_019c766a-aa9f-7ed0-b4fc-3ef0d732416f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerAssetAllowanceForCreditLossWriteoff_019c766a-aa9f-7857-b2b2-d061eea414f8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContractWithCustomerAssetAllowanceForCreditLossWriteoff"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerAssetAllowanceForCreditLossRollForward_019c766a-aa9f-76f9-b8a1-ddf0fac5ead2" xlink:to="loc_us-gaap_ContractWithCustomerAssetAllowanceForCreditLossWriteoff_019c766a-aa9f-7857-b2b2-d061eea414f8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_OffBalanceSheetCreditLossLiabilityAllowanceForCreditLossRecovery_019c766a-aa9f-7b5b-abb4-4a6996fc9da7" xlink:href="hood-20251231.xsd#hood_OffBalanceSheetCreditLossLiabilityAllowanceForCreditLossRecovery"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerAssetAllowanceForCreditLossRollForward_019c766a-aa9f-76f9-b8a1-ddf0fac5ead2" xlink:to="loc_hood_OffBalanceSheetCreditLossLiabilityAllowanceForCreditLossRecovery_019c766a-aa9f-7b5b-abb4-4a6996fc9da7" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerReceivableAllowanceForCreditLoss_019c766a-aa9f-79a8-a714-76ac32d5c3a6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContractWithCustomerReceivableAllowanceForCreditLoss"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/ALLOWANCEFORCREDITLOSSESCreditCardReceivableAgingAnalysisDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#ALLOWANCEFORCREDITLOSSESCreditCardReceivableAgingAnalysisDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/ALLOWANCEFORCREDITLOSSESCreditCardReceivableAgingAnalysisDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_019c766a-aa9f-72b9-9a68-804d28bd411a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_019c766a-aa9f-7f7d-870d-5471b425d14b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfFinancingReceivablesPastDueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_019c766a-aa9f-72b9-9a68-804d28bd411a" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_019c766a-aa9f-7f7d-870d-5471b425d14b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019c766a-aa9f-710f-91cd-152c68d40c02" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_019c766a-aa9f-7f7d-870d-5471b425d14b" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019c766a-aa9f-710f-91cd-152c68d40c02" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019c766a-aa9f-710f-91cd-152c68d40c02_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019c766a-aa9f-710f-91cd-152c68d40c02" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019c766a-aa9f-710f-91cd-152c68d40c02_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019c766a-aa9f-7d9c-b774-3c26d5529cbd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019c766a-aa9f-710f-91cd-152c68d40c02" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019c766a-aa9f-7d9c-b774-3c26d5529cbd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditCardReceivablesMember_019c766a-aa9f-7f26-973b-f6f0defcb3fd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditCardReceivablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019c766a-aa9f-7d9c-b774-3c26d5529cbd" xlink:to="loc_us-gaap_CreditCardReceivablesMember_019c766a-aa9f-7f26-973b-f6f0defcb3fd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_019c766a-aa9f-7c98-aa98-d7b2575bca5f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivablesPeriodPastDueAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_019c766a-aa9f-7f7d-870d-5471b425d14b" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_019c766a-aa9f-7c98-aa98-d7b2575bca5f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019c766a-aa9f-7c98-aa98-d7b2575bca5f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivablesPeriodPastDueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_019c766a-aa9f-7c98-aa98-d7b2575bca5f" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019c766a-aa9f-7c98-aa98-d7b2575bca5f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019c766a-aa9f-7c1b-ba39-c6c945cbb442" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivablesPeriodPastDueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_019c766a-aa9f-7c98-aa98-d7b2575bca5f" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019c766a-aa9f-7c1b-ba39-c6c945cbb442" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialAssetNotPastDueMember_019c766a-aa9f-7902-8365-703bf19684ae" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancialAssetNotPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019c766a-aa9f-7c1b-ba39-c6c945cbb442" xlink:to="loc_us-gaap_FinancialAssetNotPastDueMember_019c766a-aa9f-7902-8365-703bf19684ae" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialAssetPastDueMember_019c766a-aa9f-7ada-806b-1fcd32d99b68" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancialAssetPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_019c766a-aa9f-7c1b-ba39-c6c945cbb442" xlink:to="loc_us-gaap_FinancialAssetPastDueMember_019c766a-aa9f-7ada-806b-1fcd32d99b68" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_FinancialAssetLessThan90DaysPastDueMember_019c766a-aa9f-7352-a6b6-67c7258eaf0d" xlink:href="hood-20251231.xsd#hood_FinancialAssetLessThan90DaysPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialAssetPastDueMember_019c766a-aa9f-7ada-806b-1fcd32d99b68" xlink:to="loc_hood_FinancialAssetLessThan90DaysPastDueMember_019c766a-aa9f-7352-a6b6-67c7258eaf0d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember_019c766a-aa9f-7468-9795-ff59a2d944f3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialAssetPastDueMember_019c766a-aa9f-7ada-806b-1fcd32d99b68" xlink:to="loc_us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember_019c766a-aa9f-7468-9795-ff59a2d944f3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerReceivableAfterAllowanceForCreditLossCurrent_019c766a-aa9f-72e2-93aa-4fdf0a3a0747" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContractWithCustomerReceivableAfterAllowanceForCreditLossCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_019c766a-aa9f-72b9-9a68-804d28bd411a" xlink:to="loc_us-gaap_ContractWithCustomerReceivableAfterAllowanceForCreditLossCurrent_019c766a-aa9f-72e2-93aa-4fdf0a3a0747" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_OffBalanceSheetCreditCardReceivableAsset_019c766a-aa9f-778c-9cc1-a2f6e262b0a7" xlink:href="hood-20251231.xsd#hood_OffBalanceSheetCreditCardReceivableAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_019c766a-aa9f-72b9-9a68-804d28bd411a" xlink:to="loc_hood_OffBalanceSheetCreditCardReceivableAsset_019c766a-aa9f-778c-9cc1-a2f6e262b0a7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss_019c766a-aa9f-72ca-b51c-68f14018790d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_019c766a-aa9f-72b9-9a68-804d28bd411a" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss_019c766a-aa9f-72ca-b51c-68f14018790d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_FinancingReceivableAfterAllowanceForCreditLossToTotalPercent_019c766a-aa9f-7841-a0af-7b5b71223516" xlink:href="hood-20251231.xsd#hood_FinancingReceivableAfterAllowanceForCreditLossToTotalPercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_019c766a-aa9f-72b9-9a68-804d28bd411a" xlink:to="loc_hood_FinancingReceivableAfterAllowanceForCreditLossToTotalPercent_019c766a-aa9f-7841-a0af-7b5b71223516" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/ALLOWANCEFORCREDITLOSSESCreditQualityIndicatorsDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#ALLOWANCEFORCREDITLOSSESCreditQualityIndicatorsDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/ALLOWANCEFORCREDITLOSSESCreditQualityIndicatorsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019c766a-aa9f-7b3e-9449-2961cd975e6e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableRecordedInvestmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_019c766a-aa9f-715c-a911-76c58a9b8dd4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019c766a-aa9f-7b3e-9449-2961cd975e6e" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_019c766a-aa9f-715c-a911-76c58a9b8dd4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditScoreFicoAxis_019c766a-aa9f-7378-a8dc-cf63f6e104a6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditScoreFicoAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_019c766a-aa9f-715c-a911-76c58a9b8dd4" xlink:to="loc_us-gaap_CreditScoreFicoAxis_019c766a-aa9f-7378-a8dc-cf63f6e104a6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditScoreFicoDomain_019c766a-aa9f-7378-a8dc-cf63f6e104a6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditScoreFicoDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditScoreFicoAxis_019c766a-aa9f-7378-a8dc-cf63f6e104a6" xlink:to="loc_us-gaap_CreditScoreFicoDomain_019c766a-aa9f-7378-a8dc-cf63f6e104a6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditScoreFicoDomain_019c766a-aa9f-7c0c-934a-0b61a0c88064" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditScoreFicoDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditScoreFicoAxis_019c766a-aa9f-7378-a8dc-cf63f6e104a6" xlink:to="loc_us-gaap_CreditScoreFicoDomain_019c766a-aa9f-7c0c-934a-0b61a0c88064" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_FICOScoreLessThan640Member_019c766a-aa9f-7d58-b7e8-c6ce950f8a84" xlink:href="hood-20251231.xsd#hood_FICOScoreLessThan640Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditScoreFicoDomain_019c766a-aa9f-7c0c-934a-0b61a0c88064" xlink:to="loc_hood_FICOScoreLessThan640Member_019c766a-aa9f-7d58-b7e8-c6ce950f8a84" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_FICOScore640To690Member_019c766a-aa9f-7ac5-aab7-1c7850e7d064" xlink:href="hood-20251231.xsd#hood_FICOScore640To690Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditScoreFicoDomain_019c766a-aa9f-7c0c-934a-0b61a0c88064" xlink:to="loc_hood_FICOScore640To690Member_019c766a-aa9f-7ac5-aab7-1c7850e7d064" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_FICOScoreGreaterThan690Member_019c766a-aa9f-740d-8ff3-48d8eb891a92" xlink:href="hood-20251231.xsd#hood_FICOScoreGreaterThan690Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditScoreFicoDomain_019c766a-aa9f-7c0c-934a-0b61a0c88064" xlink:to="loc_hood_FICOScoreGreaterThan690Member_019c766a-aa9f-740d-8ff3-48d8eb891a92" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019c766a-aa9f-7542-894e-93945013b9ff" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_019c766a-aa9f-715c-a911-76c58a9b8dd4" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019c766a-aa9f-7542-894e-93945013b9ff" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019c766a-aa9f-7542-894e-93945013b9ff_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019c766a-aa9f-7542-894e-93945013b9ff" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019c766a-aa9f-7542-894e-93945013b9ff_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019c766a-aa9f-79d2-8240-d97e30a2b270" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_019c766a-aa9f-7542-894e-93945013b9ff" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019c766a-aa9f-79d2-8240-d97e30a2b270" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditCardReceivablesMember_019c766a-aa9f-75f1-91ee-df6c6d02f0e2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditCardReceivablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_019c766a-aa9f-79d2-8240-d97e30a2b270" xlink:to="loc_us-gaap_CreditCardReceivablesMember_019c766a-aa9f-75f1-91ee-df6c6d02f0e2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss_019c766a-aa9f-7204-8b05-34094a44af00" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019c766a-aa9f-7b3e-9449-2961cd975e6e" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss_019c766a-aa9f-7204-8b05-34094a44af00" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLossPercent_019c766a-aa9f-7a6c-8746-266d48870bdc" xlink:href="hood-20251231.xsd#hood_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLossPercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_019c766a-aa9f-7b3e-9449-2961cd975e6e" xlink:to="loc_hood_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLossPercent_019c766a-aa9f-7a6c-8746-266d48870bdc" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/INVESTMENTSANDFAIRVALUEMEASUREMENTNarrativeDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#INVESTMENTSANDFAIRVALUEMEASUREMENTNarrativeDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/INVESTMENTSANDFAIRVALUEMEASUREMENTNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019c766a-aa9f-79c7-8015-827fde1eb3ea" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureOfAssetAndLiabilityNotMeasuredAtFairValueTable_019c766a-aa9f-793e-8be6-c839ae69f045" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueDisclosureOfAssetAndLiabilityNotMeasuredAtFairValueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019c766a-aa9f-79c7-8015-827fde1eb3ea" xlink:to="loc_us-gaap_FairValueDisclosureOfAssetAndLiabilityNotMeasuredAtFairValueTable_019c766a-aa9f-793e-8be6-c839ae69f045" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAxis_019c766a-aa9f-72c0-8086-f8a6cfdeffc7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashAndCashEquivalentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueDisclosureOfAssetAndLiabilityNotMeasuredAtFairValueTable_019c766a-aa9f-793e-8be6-c839ae69f045" xlink:to="loc_us-gaap_CashAndCashEquivalentsAxis_019c766a-aa9f-72c0-8086-f8a6cfdeffc7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019c766a-aa9f-72c0-8086-f8a6cfdeffc7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CashAndCashEquivalentsAxis_019c766a-aa9f-72c0-8086-f8a6cfdeffc7" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019c766a-aa9f-72c0-8086-f8a6cfdeffc7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019c766a-aa9f-776d-9eb0-240a4b13c006" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CashAndCashEquivalentsAxis_019c766a-aa9f-72c0-8086-f8a6cfdeffc7" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019c766a-aa9f-776d-9eb0-240a4b13c006" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BankTimeDepositsMember_019c766a-aa9f-76d4-9bfe-068f4cd4b5a0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BankTimeDepositsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019c766a-aa9f-776d-9eb0-240a4b13c006" xlink:to="loc_us-gaap_BankTimeDepositsMember_019c766a-aa9f-76d4-9bfe-068f4cd4b5a0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterestCurrent_019c766a-aa9f-7991-aed1-c45e16993177" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterestCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019c766a-aa9f-79c7-8015-827fde1eb3ea" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterestCurrent_019c766a-aa9f-7991-aed1-c45e16993177" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleOfHeldToMaturitySecurities_019c766a-aa9f-74c8-aaa0-3dc0da0482df" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromSaleOfHeldToMaturitySecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019c766a-aa9f-79c7-8015-827fde1eb3ea" xlink:to="loc_us-gaap_ProceedsFromSaleOfHeldToMaturitySecurities_019c766a-aa9f-74c8-aaa0-3dc0da0482df" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/INVESTMENTSANDFAIRVALUEMEASUREMENTHeldToMaturityInvestmentsDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#INVESTMENTSANDFAIRVALUEMEASUREMENTHeldToMaturityInvestmentsDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/INVESTMENTSANDFAIRVALUEMEASUREMENTHeldToMaturityInvestmentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019c766a-aa9f-7757-83f8-09ad2b0aa9b6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019c766a-aa9f-7bb7-a19c-2b76943c6c89" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019c766a-aa9f-7757-83f8-09ad2b0aa9b6" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019c766a-aa9f-7bb7-a19c-2b76943c6c89" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_019c766a-aa9f-7cb1-bcaa-08c5b9ba8e4b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019c766a-aa9f-7bb7-a19c-2b76943c6c89" xlink:to="loc_us-gaap_FinancialInstrumentAxis_019c766a-aa9f-7cb1-bcaa-08c5b9ba8e4b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-7cb1-bcaa-08c5b9ba8e4b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019c766a-aa9f-7cb1-bcaa-08c5b9ba8e4b" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-7cb1-bcaa-08c5b9ba8e4b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-7d55-8632-dde1705be414" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019c766a-aa9f-7cb1-bcaa-08c5b9ba8e4b" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-7d55-8632-dde1705be414" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasurySecuritiesMember_019c766a-aa9f-7e65-9e87-27384568a1b3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_USTreasurySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-7d55-8632-dde1705be414" xlink:to="loc_us-gaap_USTreasurySecuritiesMember_019c766a-aa9f-7e65-9e87-27384568a1b3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateBondSecuritiesMember_019c766a-aa9f-7c88-b5ac-b3d746059a00" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CorporateBondSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-7d55-8632-dde1705be414" xlink:to="loc_us-gaap_CorporateBondSecuritiesMember_019c766a-aa9f-7c88-b5ac-b3d746059a00" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_019c766a-aa9f-725e-a926-695c139da9ce" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_USGovernmentAgenciesDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-7d55-8632-dde1705be414" xlink:to="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_019c766a-aa9f-725e-a926-695c139da9ce" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestNonaccrualNoAllowance_019c766a-aa9f-727b-a2c4-b2a17e9587ba" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestNonaccrualNoAllowance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019c766a-aa9f-7757-83f8-09ad2b0aa9b6" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestNonaccrualNoAllowance_019c766a-aa9f-727b-a2c4-b2a17e9587ba" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLoss_019c766a-aa9f-768d-9e1e-c66716ac0d7a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019c766a-aa9f-7757-83f8-09ad2b0aa9b6" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLoss_019c766a-aa9f-768d-9e1e-c66716ac0d7a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain_019c766a-aa9f-72e5-859e-0604f4327a78" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019c766a-aa9f-7757-83f8-09ad2b0aa9b6" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain_019c766a-aa9f-72e5-859e-0604f4327a78" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss_019c766a-aa9f-77e9-a881-7d094e93f4fe" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019c766a-aa9f-7757-83f8-09ad2b0aa9b6" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss_019c766a-aa9f-77e9-a881-7d094e93f4fe" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesFairValue_019c766a-aa9f-75b5-83f1-2d8f949debfd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HeldToMaturitySecuritiesFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_019c766a-aa9f-7757-83f8-09ad2b0aa9b6" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesFairValue_019c766a-aa9f-75b5-83f1-2d8f949debfd" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/INVESTMENTSANDFAIRVALUEMEASUREMENTAmortizedCostAndFairValueOfHeldToMaturityInvestmentsByContractualMaturityDateDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#INVESTMENTSANDFAIRVALUEMEASUREMENTAmortizedCostAndFairValueOfHeldToMaturityInvestmentsByContractualMaturityDateDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/INVESTMENTSANDFAIRVALUEMEASUREMENTAmortizedCostAndFairValueOfHeldToMaturityInvestmentsByContractualMaturityDateDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureAssetAndLiabilityNotMeasuredAtFairValueLineItems_019c766a-aa9f-73c8-97a9-6ea728b0d104" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueDisclosureAssetAndLiabilityNotMeasuredAtFairValueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureOfAssetAndLiabilityNotMeasuredAtFairValueTable_019c766a-aa9f-79e7-bcb8-ce8fe749bb7c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueDisclosureOfAssetAndLiabilityNotMeasuredAtFairValueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueDisclosureAssetAndLiabilityNotMeasuredAtFairValueLineItems_019c766a-aa9f-73c8-97a9-6ea728b0d104" xlink:to="loc_us-gaap_FairValueDisclosureOfAssetAndLiabilityNotMeasuredAtFairValueTable_019c766a-aa9f-79e7-bcb8-ce8fe749bb7c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_019c766a-aa9f-7bda-81b8-0617c68dcb7e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueDisclosureOfAssetAndLiabilityNotMeasuredAtFairValueTable_019c766a-aa9f-79e7-bcb8-ce8fe749bb7c" xlink:to="loc_us-gaap_FinancialInstrumentAxis_019c766a-aa9f-7bda-81b8-0617c68dcb7e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-7bda-81b8-0617c68dcb7e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019c766a-aa9f-7bda-81b8-0617c68dcb7e" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-7bda-81b8-0617c68dcb7e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-78ed-aea1-08029235ea2f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019c766a-aa9f-7bda-81b8-0617c68dcb7e" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-78ed-aea1-08029235ea2f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasurySecuritiesMember_019c766a-aa9f-7b46-bc2a-182318310f6d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_USTreasurySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-78ed-aea1-08029235ea2f" xlink:to="loc_us-gaap_USTreasurySecuritiesMember_019c766a-aa9f-7b46-bc2a-182318310f6d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateBondSecuritiesMember_019c766a-aa9f-7f8d-833a-a3950ef79f68" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CorporateBondSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-78ed-aea1-08029235ea2f" xlink:to="loc_us-gaap_CorporateBondSecuritiesMember_019c766a-aa9f-7f8d-833a-a3950ef79f68" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_019c766a-aa9f-7226-86b5-c42f1a6b8a3a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_USGovernmentAgenciesDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-78ed-aea1-08029235ea2f" xlink:to="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_019c766a-aa9f-7226-86b5-c42f1a6b8a3a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossMaturityAllocatedAndSingleMaturityDateAbstract_019c766a-aa9f-706b-aee9-6c2f36d7dd2d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtSecuritiesHeldToMaturityAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossMaturityAllocatedAndSingleMaturityDateAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureAssetAndLiabilityNotMeasuredAtFairValueLineItems_019c766a-aa9f-73c8-97a9-6ea728b0d104" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossMaturityAllocatedAndSingleMaturityDateAbstract_019c766a-aa9f-706b-aee9-6c2f36d7dd2d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossMaturityAllocatedAndSingleMaturityDateYearOne_019c766a-aa9f-7c39-a17e-ca5af18c7c8b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtSecuritiesHeldToMaturityAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossMaturityAllocatedAndSingleMaturityDateYearOne"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesHeldToMaturityAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossMaturityAllocatedAndSingleMaturityDateAbstract_019c766a-aa9f-706b-aee9-6c2f36d7dd2d" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossMaturityAllocatedAndSingleMaturityDateYearOne_019c766a-aa9f-7c39-a17e-ca5af18c7c8b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_DebtSecuritiesHeldToMaturityAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossMaturityAllocatedAndSingleMaturityDateAfterYearOneThroughTwo_019c766a-aa9f-7c95-be61-16bf3d1df571" xlink:href="hood-20251231.xsd#hood_DebtSecuritiesHeldToMaturityAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossMaturityAllocatedAndSingleMaturityDateAfterYearOneThroughTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesHeldToMaturityAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossMaturityAllocatedAndSingleMaturityDateAbstract_019c766a-aa9f-706b-aee9-6c2f36d7dd2d" xlink:to="loc_hood_DebtSecuritiesHeldToMaturityAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossMaturityAllocatedAndSingleMaturityDateAfterYearOneThroughTwo_019c766a-aa9f-7c95-be61-16bf3d1df571" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestNonaccrualNoAllowance_019c766a-aa9f-7b1d-83e1-167d15367439" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestNonaccrualNoAllowance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesHeldToMaturityAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossMaturityAllocatedAndSingleMaturityDateAbstract_019c766a-aa9f-706b-aee9-6c2f36d7dd2d" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestNonaccrualNoAllowance_019c766a-aa9f-7b1d-83e1-167d15367439" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValueAbstract_019c766a-aa9f-79a4-88e4-4a7d4a62cf4a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValueAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureAssetAndLiabilityNotMeasuredAtFairValueLineItems_019c766a-aa9f-73c8-97a9-6ea728b0d104" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValueAbstract_019c766a-aa9f-79a4-88e4-4a7d4a62cf4a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue_019c766a-aa9f-757a-a820-a895359264af" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValueAbstract_019c766a-aa9f-79a4-88e4-4a7d4a62cf4a" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue_019c766a-aa9f-757a-a820-a895359264af" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_DebtSecuritiesHeldToMaturityFairValueMaturityAllocatedAndSingleMaturityDateAfterYearOneAndTwo_019c766a-aa9f-7099-9877-13a0cf7dc9a3" xlink:href="hood-20251231.xsd#hood_DebtSecuritiesHeldToMaturityFairValueMaturityAllocatedAndSingleMaturityDateAfterYearOneAndTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValueAbstract_019c766a-aa9f-79a4-88e4-4a7d4a62cf4a" xlink:to="loc_hood_DebtSecuritiesHeldToMaturityFairValueMaturityAllocatedAndSingleMaturityDateAfterYearOneAndTwo_019c766a-aa9f-7099-9877-13a0cf7dc9a3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesFairValue_019c766a-aa9f-7df9-b079-381b4ec24294" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HeldToMaturitySecuritiesFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValueAbstract_019c766a-aa9f-79a4-88e4-4a7d4a62cf4a" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesFairValue_019c766a-aa9f-7df9-b079-381b4ec24294" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/INVESTMENTSANDFAIRVALUEMEASUREMENTScheduleofFinancialAssetandLiabilitiesMeasuredAtFairValueOnaRecurringBasisDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#INVESTMENTSANDFAIRVALUEMEASUREMENTScheduleofFinancialAssetandLiabilitiesMeasuredAtFairValueOnaRecurringBasisDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/INVESTMENTSANDFAIRVALUEMEASUREMENTScheduleofFinancialAssetandLiabilitiesMeasuredAtFairValueOnaRecurringBasisDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019c766a-aa9f-76f6-943f-ae6e9c2ee877" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019c766a-aa9f-719a-b884-25837741a655" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019c766a-aa9f-76f6-943f-ae6e9c2ee877" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019c766a-aa9f-719a-b884-25837741a655" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019c766a-aa9f-7675-8ad9-37790124d68d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019c766a-aa9f-719a-b884-25837741a655" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019c766a-aa9f-7675-8ad9-37790124d68d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_019c766a-aa9f-7675-8ad9-37790124d68d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019c766a-aa9f-7675-8ad9-37790124d68d" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_019c766a-aa9f-7675-8ad9-37790124d68d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_019c766a-aa9f-70d7-a81c-b0b1f658e64b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019c766a-aa9f-7675-8ad9-37790124d68d" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_019c766a-aa9f-70d7-a81c-b0b1f658e64b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_019c766a-aa9f-7df5-92ae-3b1caadb2b9e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_019c766a-aa9f-70d7-a81c-b0b1f658e64b" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_019c766a-aa9f-7df5-92ae-3b1caadb2b9e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019c766a-aa9f-7e6e-8eda-0934d1fbc95e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019c766a-aa9f-719a-b884-25837741a655" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019c766a-aa9f-7e6e-8eda-0934d1fbc95e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019c766a-aa9f-7e6e-8eda-0934d1fbc95e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019c766a-aa9f-7e6e-8eda-0934d1fbc95e" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019c766a-aa9f-7e6e-8eda-0934d1fbc95e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019c766a-aa9f-771c-b54e-86f704f7d37e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019c766a-aa9f-7e6e-8eda-0934d1fbc95e" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019c766a-aa9f-771c-b54e-86f704f7d37e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_019c766a-aa9f-72e7-8756-78adf435049b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019c766a-aa9f-771c-b54e-86f704f7d37e" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_019c766a-aa9f-72e7-8756-78adf435049b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_019c766a-aa9f-7341-8920-cc2dc6c2ea7e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019c766a-aa9f-771c-b54e-86f704f7d37e" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_019c766a-aa9f-7341-8920-cc2dc6c2ea7e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_019c766a-aa9f-7a1b-9a26-70e0eaad1c48" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019c766a-aa9f-771c-b54e-86f704f7d37e" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_019c766a-aa9f-7a1b-9a26-70e0eaad1c48" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAxis_019c766a-aa9f-7dee-a284-5efe3d8d6626" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashAndCashEquivalentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019c766a-aa9f-719a-b884-25837741a655" xlink:to="loc_us-gaap_CashAndCashEquivalentsAxis_019c766a-aa9f-7dee-a284-5efe3d8d6626" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019c766a-aa9f-7dee-a284-5efe3d8d6626_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CashAndCashEquivalentsAxis_019c766a-aa9f-7dee-a284-5efe3d8d6626" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019c766a-aa9f-7dee-a284-5efe3d8d6626_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019c766a-aa9f-778b-92d7-ed4905f93742" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CashAndCashEquivalentsAxis_019c766a-aa9f-7dee-a284-5efe3d8d6626" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019c766a-aa9f-778b-92d7-ed4905f93742" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BankTimeDepositsMember_019c766a-aa9f-73d6-9455-071496fc63e7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BankTimeDepositsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019c766a-aa9f-778b-92d7-ed4905f93742" xlink:to="loc_us-gaap_BankTimeDepositsMember_019c766a-aa9f-73d6-9455-071496fc63e7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MoneyMarketFundsMember_019c766a-aa9f-7e95-8201-3a8225853fe4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MoneyMarketFundsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019c766a-aa9f-778b-92d7-ed4905f93742" xlink:to="loc_us-gaap_MoneyMarketFundsMember_019c766a-aa9f-7e95-8201-3a8225853fe4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_019c766a-aa9f-7bc7-8a09-f39de40d55a9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019c766a-aa9f-719a-b884-25837741a655" xlink:to="loc_us-gaap_FinancialInstrumentAxis_019c766a-aa9f-7bc7-8a09-f39de40d55a9" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-7bc7-8a09-f39de40d55a9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019c766a-aa9f-7bc7-8a09-f39de40d55a9" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-7bc7-8a09-f39de40d55a9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-7d66-b064-36d1b7c7aa0b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019c766a-aa9f-7bc7-8a09-f39de40d55a9" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-7d66-b064-36d1b7c7aa0b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasurySecuritiesMember_019c766a-aa9f-7afe-80bf-e7eb4b5ecc06" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_USTreasurySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-7d66-b064-36d1b7c7aa0b" xlink:to="loc_us-gaap_USTreasurySecuritiesMember_019c766a-aa9f-7afe-80bf-e7eb4b5ecc06" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_ForeignTreasurySecuritiesMember_019c766a-aa9f-7b3f-a9f3-f698fe43c569" xlink:href="hood-20251231.xsd#hood_ForeignTreasurySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-7d66-b064-36d1b7c7aa0b" xlink:to="loc_hood_ForeignTreasurySecuritiesMember_019c766a-aa9f-7b3f-a9f3-f698fe43c569" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_StablecoinMember_019c766a-aa9f-7ccc-83a8-b8d8b8a4871b" xlink:href="hood-20251231.xsd#hood_StablecoinMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-7d66-b064-36d1b7c7aa0b" xlink:to="loc_hood_StablecoinMember_019c766a-aa9f-7ccc-83a8-b8d8b8a4871b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_EquitySecuritiesSecuritiesOwnedMember_019c766a-aa9f-789c-aace-24dd5730cb3e" xlink:href="hood-20251231.xsd#hood_EquitySecuritiesSecuritiesOwnedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-7d66-b064-36d1b7c7aa0b" xlink:to="loc_hood_EquitySecuritiesSecuritiesOwnedMember_019c766a-aa9f-789c-aace-24dd5730cb3e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_NonMarketableSecuritiesMember_019c766a-aa9f-7b09-b879-3396f3d04b1c" xlink:href="hood-20251231.xsd#hood_NonMarketableSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-7d66-b064-36d1b7c7aa0b" xlink:to="loc_hood_NonMarketableSecuritiesMember_019c766a-aa9f-7b09-b879-3396f3d04b1c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepositsMember_019c766a-aa9f-740a-addf-7a8b441ec9ab" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DepositsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-7d66-b064-36d1b7c7aa0b" xlink:to="loc_us-gaap_DepositsMember_019c766a-aa9f-740a-addf-7a8b441ec9ab" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_EquitySecuritiesUserHeldFractionalSharesMember_019c766a-aa9f-7bf6-ac23-6f6c810d8fd5" xlink:href="hood-20251231.xsd#hood_EquitySecuritiesUserHeldFractionalSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-7d66-b064-36d1b7c7aa0b" xlink:to="loc_hood_EquitySecuritiesUserHeldFractionalSharesMember_019c766a-aa9f-7bf6-ac23-6f6c810d8fd5" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_EquitySecuritiesFractionalShareRepurchaseObligationsMember_019c766a-aa9f-71a5-a48d-1da109a5a0cf" xlink:href="hood-20251231.xsd#hood_EquitySecuritiesFractionalShareRepurchaseObligationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-7d66-b064-36d1b7c7aa0b" xlink:to="loc_hood_EquitySecuritiesFractionalShareRepurchaseObligationsMember_019c766a-aa9f-71a5-a48d-1da109a5a0cf" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_EventContractsMember_019c766a-aa9f-768e-9605-be41f8fb70ce" xlink:href="hood-20251231.xsd#hood_EventContractsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-7d66-b064-36d1b7c7aa0b" xlink:to="loc_hood_EventContractsMember_019c766a-aa9f-768e-9605-be41f8fb70ce" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosureAbstract_019c766a-aa9f-7a60-baf3-6416c8e12b4f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsFairValueDisclosureAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019c766a-aa9f-76f6-943f-ae6e9c2ee877" xlink:to="loc_us-gaap_AssetsFairValueDisclosureAbstract_019c766a-aa9f-7a60-baf3-6416c8e12b4f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_019c766a-aa9f-72f5-ba6d-f8202c2e4af3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_019c766a-aa9f-7a60-baf3-6416c8e12b4f" xlink:to="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_019c766a-aa9f-72f5-ba6d-f8202c2e4af3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_CashAndSecuritiesSegregatedUnderFederalAndOtherRegulationsFairValue_019c766a-aa9f-7e12-85ad-95137830138b" xlink:href="hood-20251231.xsd#hood_CashAndSecuritiesSegregatedUnderFederalAndOtherRegulationsFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_019c766a-aa9f-7a60-baf3-6416c8e12b4f" xlink:to="loc_hood_CashAndSecuritiesSegregatedUnderFederalAndOtherRegulationsFairValue_019c766a-aa9f-7e12-85ad-95137830138b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepositsWithClearingOrganizationsAndOthersSecurities_019c766a-aa9f-7d17-9dc9-59d9fc3c3475" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DepositsWithClearingOrganizationsAndOthersSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_019c766a-aa9f-7a60-baf3-6416c8e12b4f" xlink:to="loc_us-gaap_DepositsWithClearingOrganizationsAndOthersSecurities_019c766a-aa9f-7d17-9dc9-59d9fc3c3475" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsFairValueDisclosure_019c766a-aa9f-719e-958d-2e5232972d52" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherAssetsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_019c766a-aa9f-7a60-baf3-6416c8e12b4f" xlink:to="loc_us-gaap_OtherAssetsFairValueDisclosure_019c766a-aa9f-719e-958d-2e5232972d52" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_019c766a-aa9f-757b-9598-6ce79dacd1c3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_019c766a-aa9f-7a60-baf3-6416c8e12b4f" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_019c766a-aa9f-757b-9598-6ce79dacd1c3" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_019c766a-aa9f-7b2c-9952-becb368c749e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesFairValueDisclosureAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019c766a-aa9f-76f6-943f-ae6e9c2ee877" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_019c766a-aa9f-7b2c-9952-becb368c749e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesFairValueDisclosure_019c766a-aa9f-75de-a768-53e64df5e034" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherLiabilitiesFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_019c766a-aa9f-7b2c-9952-becb368c749e" xlink:to="loc_us-gaap_OtherLiabilitiesFairValueDisclosure_019c766a-aa9f-75de-a768-53e64df5e034" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosure_019c766a-aa9f-738c-b650-12bb77203d3f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_019c766a-aa9f-7b2c-9952-becb368c749e" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosure_019c766a-aa9f-738c-b650-12bb77203d3f" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/INVESTMENTSANDFAIRVALUEMEASUREMENTScheduleofChangesintheEstimatedFairValueofRobinhoodVenturesFundInvestmentsinNonMarketableEquitySecuritiesDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#INVESTMENTSANDFAIRVALUEMEASUREMENTScheduleofChangesintheEstimatedFairValueofRobinhoodVenturesFundInvestmentsinNonMarketableEquitySecuritiesDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/INVESTMENTSANDFAIRVALUEMEASUREMENTScheduleofChangesintheEstimatedFairValueofRobinhoodVenturesFundInvestmentsinNonMarketableEquitySecuritiesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019c766a-aa9f-70b5-a2d8-1d2fb24d9591" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019c766a-aa9f-76f1-957b-5a78134e31ed" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019c766a-aa9f-70b5-a2d8-1d2fb24d9591" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019c766a-aa9f-76f1-957b-5a78134e31ed" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByAssetClassAxis_019c766a-aa9f-7a2d-bdfe-c8cad0e98656" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByAssetClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019c766a-aa9f-76f1-957b-5a78134e31ed" xlink:to="loc_us-gaap_FairValueByAssetClassAxis_019c766a-aa9f-7a2d-bdfe-c8cad0e98656" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019c766a-aa9f-7a2d-bdfe-c8cad0e98656_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_019c766a-aa9f-7a2d-bdfe-c8cad0e98656" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019c766a-aa9f-7a2d-bdfe-c8cad0e98656_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019c766a-aa9f-7c5c-851b-d7ddf3633e8d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_019c766a-aa9f-7a2d-bdfe-c8cad0e98656" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019c766a-aa9f-7c5c-851b-d7ddf3633e8d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesMember_019c766a-aa9f-78f2-89ef-0a6ad8756578" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquitySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019c766a-aa9f-7c5c-851b-d7ddf3633e8d" xlink:to="loc_us-gaap_EquitySecuritiesMember_019c766a-aa9f-78f2-89ef-0a6ad8756578" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentsInAndAdvancesToAffiliatesAtFairValueRollForward_019c766a-aa9f-718a-9578-309cc7a8b14c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InvestmentsInAndAdvancesToAffiliatesAtFairValueRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019c766a-aa9f-70b5-a2d8-1d2fb24d9591" xlink:to="loc_us-gaap_InvestmentsInAndAdvancesToAffiliatesAtFairValueRollForward_019c766a-aa9f-718a-9578-309cc7a8b14c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_019c766a-aa9f-70a5-8c52-983c8dea85d3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentsInAndAdvancesToAffiliatesAtFairValueRollForward_019c766a-aa9f-718a-9578-309cc7a8b14c" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_019c766a-aa9f-70a5-8c52-983c8dea85d3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases_019c766a-aa9f-714b-a7c5-2c7b669d9193" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentsInAndAdvancesToAffiliatesAtFairValueRollForward_019c766a-aa9f-718a-9578-309cc7a8b14c" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases_019c766a-aa9f-714b-a7c5-2c7b669d9193" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss_019c766a-aa9f-79d3-9760-819f64acb8f2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentsInAndAdvancesToAffiliatesAtFairValueRollForward_019c766a-aa9f-718a-9578-309cc7a8b14c" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss_019c766a-aa9f-79d3-9760-819f64acb8f2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_019c766a-aa9f-7ed6-9818-46e36e8ebf8b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/INVESTMENTSANDFAIRVALUEMEASUREMENTScheduleofFinancialAssetandLiabilitiesMeasuredAtFairValueOnaNonRecurringBasisDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#INVESTMENTSANDFAIRVALUEMEASUREMENTScheduleofFinancialAssetandLiabilitiesMeasuredAtFairValueOnaNonRecurringBasisDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/INVESTMENTSANDFAIRVALUEMEASUREMENTScheduleofFinancialAssetandLiabilitiesMeasuredAtFairValueOnaNonRecurringBasisDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019c766a-aa9f-79f2-a059-545fcd942178" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019c766a-aa9f-797d-9fd7-b5d4454ba7eb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019c766a-aa9f-79f2-a059-545fcd942178" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019c766a-aa9f-797d-9fd7-b5d4454ba7eb" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019c766a-aa9f-7c59-9466-4c582244cd74" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019c766a-aa9f-797d-9fd7-b5d4454ba7eb" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019c766a-aa9f-7c59-9466-4c582244cd74" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019c766a-aa9f-7c59-9466-4c582244cd74_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019c766a-aa9f-7c59-9466-4c582244cd74" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019c766a-aa9f-7c59-9466-4c582244cd74_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019c766a-aa9f-7527-820e-a29931d9cc50" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019c766a-aa9f-7c59-9466-4c582244cd74" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019c766a-aa9f-7527-820e-a29931d9cc50" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_019c766a-aa9f-77d1-ac5a-ab8c007b9bf2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019c766a-aa9f-7527-820e-a29931d9cc50" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_019c766a-aa9f-77d1-ac5a-ab8c007b9bf2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_019c766a-aa9f-7852-8888-1bc04fbb24d0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019c766a-aa9f-7527-820e-a29931d9cc50" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_019c766a-aa9f-7852-8888-1bc04fbb24d0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_019c766a-aa9f-75a2-888b-03ba379c7988" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019c766a-aa9f-7527-820e-a29931d9cc50" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_019c766a-aa9f-75a2-888b-03ba379c7988" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_019c766a-aa9f-7d14-ae81-501381c47612" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019c766a-aa9f-797d-9fd7-b5d4454ba7eb" xlink:to="loc_us-gaap_FinancialInstrumentAxis_019c766a-aa9f-7d14-ae81-501381c47612" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-7d14-ae81-501381c47612_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019c766a-aa9f-7d14-ae81-501381c47612" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-7d14-ae81-501381c47612_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-747a-8e42-52568aa58391" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_019c766a-aa9f-7d14-ae81-501381c47612" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-747a-8e42-52568aa58391" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasurySecuritiesMember_019c766a-aa9f-7757-b5f1-774115bbf590" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_USTreasurySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-747a-8e42-52568aa58391" xlink:to="loc_us-gaap_USTreasurySecuritiesMember_019c766a-aa9f-7757-b5f1-774115bbf590" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateBondSecuritiesMember_019c766a-aa9f-70f3-835f-9dce4f2bc4a2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CorporateBondSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-747a-8e42-52568aa58391" xlink:to="loc_us-gaap_CorporateBondSecuritiesMember_019c766a-aa9f-70f3-835f-9dce4f2bc4a2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_019c766a-aa9f-768e-93fe-3dc99d13a947" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_USGovernmentAgenciesDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_019c766a-aa9f-747a-8e42-52568aa58391" xlink:to="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_019c766a-aa9f-768e-93fe-3dc99d13a947" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_019c766a-aa9f-7ec8-b249-269fc3cdcc24" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByMeasurementBasisAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019c766a-aa9f-797d-9fd7-b5d4454ba7eb" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_019c766a-aa9f-7ec8-b249-269fc3cdcc24" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019c766a-aa9f-7ec8-b249-269fc3cdcc24_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_019c766a-aa9f-7ec8-b249-269fc3cdcc24" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019c766a-aa9f-7ec8-b249-269fc3cdcc24_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_019c766a-aa9f-766e-80a9-ce01b0504f01" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueDisclosureItemAmountsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_019c766a-aa9f-7ec8-b249-269fc3cdcc24" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_019c766a-aa9f-766e-80a9-ce01b0504f01" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019c766a-aa9f-72db-912b-c9491e1318ce" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_019c766a-aa9f-766e-80a9-ce01b0504f01" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019c766a-aa9f-72db-912b-c9491e1318ce" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_019c766a-aa9f-76ef-8668-5345d9811711" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019c766a-aa9f-72db-912b-c9491e1318ce" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_019c766a-aa9f-76ef-8668-5345d9811711" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosureAbstract_019c766a-aa9f-7367-9303-06ef0e02fbe3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsFairValueDisclosureAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_019c766a-aa9f-79f2-a059-545fcd942178" xlink:to="loc_us-gaap_AssetsFairValueDisclosureAbstract_019c766a-aa9f-7367-9303-06ef0e02fbe3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesFairValue_019c766a-aa9f-7a6d-8652-de5d5e8d1c1b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HeldToMaturitySecuritiesFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_019c766a-aa9f-7367-9303-06ef0e02fbe3" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesFairValue_019c766a-aa9f-7a6d-8652-de5d5e8d1c1b" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/INCOMETAXESDeferredTaxAssetValuationAllowanceDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#INCOMETAXESDeferredTaxAssetValuationAllowanceDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/INCOMETAXESDeferredTaxAssetValuationAllowanceDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_srt_ValuationAndQualifyingAccountsDisclosureLineItems_019c766a-aaa0-735c-9b58-6109f6767da5" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ValuationAndQualifyingAccountsDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ValuationAndQualifyingAccountsDisclosureTable_019c766a-aaa0-708f-aa15-697cb908d68e" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ValuationAndQualifyingAccountsDisclosureTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_srt_ValuationAndQualifyingAccountsDisclosureLineItems_019c766a-aaa0-735c-9b58-6109f6767da5" xlink:to="loc_srt_ValuationAndQualifyingAccountsDisclosureTable_019c766a-aaa0-708f-aa15-697cb908d68e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_019c766a-aaa0-7900-bcbe-bffcb1c2211c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ValuationAllowancesAndReservesTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_ValuationAndQualifyingAccountsDisclosureTable_019c766a-aaa0-708f-aa15-697cb908d68e" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_019c766a-aaa0-7900-bcbe-bffcb1c2211c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesDomain_019c766a-aaa0-7900-bcbe-bffcb1c2211c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ValuationAllowancesAndReservesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_019c766a-aaa0-7900-bcbe-bffcb1c2211c" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesDomain_019c766a-aaa0-7900-bcbe-bffcb1c2211c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesDomain_019c766a-aaa0-758e-85be-8cbbf7e11123" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ValuationAllowancesAndReservesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_019c766a-aaa0-7900-bcbe-bffcb1c2211c" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesDomain_019c766a-aaa0-758e-85be-8cbbf7e11123" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowanceOfDeferredTaxAssetsMember_019c766a-aaa0-754c-af17-184674b77c9c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ValuationAllowanceOfDeferredTaxAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesDomain_019c766a-aaa0-758e-85be-8cbbf7e11123" xlink:to="loc_us-gaap_ValuationAllowanceOfDeferredTaxAssetsMember_019c766a-aaa0-754c-af17-184674b77c9c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_019c766a-aaa0-7c6c-a5c7-49d5c132a5b4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MovementInValuationAllowancesAndReservesRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ValuationAndQualifyingAccountsDisclosureLineItems_019c766a-aaa0-735c-9b58-6109f6767da5" xlink:to="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_019c766a-aaa0-7c6c-a5c7-49d5c132a5b4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesBalance_019c766a-aaa0-7159-ba33-b1ccdee76cc4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ValuationAllowancesAndReservesBalance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_019c766a-aaa0-7c6c-a5c7-49d5c132a5b4" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesBalance_019c766a-aaa0-7159-ba33-b1ccdee76cc4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense_019c766a-aaa0-793a-b715-3fe9d8a4bfc9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_019c766a-aaa0-7c6c-a5c7-49d5c132a5b4" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense_019c766a-aaa0-793a-b715-3fe9d8a4bfc9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesDeductions_019c766a-aaa0-7a12-bd95-15faac96b466" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ValuationAllowancesAndReservesDeductions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_019c766a-aaa0-7c6c-a5c7-49d5c132a5b4" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesDeductions_019c766a-aaa0-7a12-bd95-15faac96b466" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesReservesOfBusinessesAcquired_019c766a-aaa0-7d59-bc6c-72f7d2bc69ba" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ValuationAllowancesAndReservesReservesOfBusinessesAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_019c766a-aaa0-7c6c-a5c7-49d5c132a5b4" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesReservesOfBusinessesAcquired_019c766a-aaa0-7d59-bc6c-72f7d2bc69ba" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesBalance_019c766a-aaa0-7690-9734-9a2a63be2a97" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ValuationAllowancesAndReservesBalance"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/INCOMETAXESNarrativeDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#INCOMETAXESNarrativeDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/INCOMETAXESNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwardsLineItems_019c766a-aaa0-72a4-807b-353705985cca" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLossCarryforwardsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwardsTable_019c766a-aaa0-7c9f-9b04-04060ece7e84" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLossCarryforwardsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_019c766a-aaa0-72a4-807b-353705985cca" xlink:to="loc_us-gaap_OperatingLossCarryforwardsTable_019c766a-aaa0-7c9f-9b04-04060ece7e84" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityAxis_019c766a-aaa0-7c03-974c-f3ce5f6f397e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxAuthorityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_OperatingLossCarryforwardsTable_019c766a-aaa0-7c9f-9b04-04060ece7e84" xlink:to="loc_us-gaap_IncomeTaxAuthorityAxis_019c766a-aaa0-7c03-974c-f3ce5f6f397e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_019c766a-aaa0-7c03-974c-f3ce5f6f397e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxAuthorityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_019c766a-aaa0-7c03-974c-f3ce5f6f397e" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_019c766a-aaa0-7c03-974c-f3ce5f6f397e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_019c766a-aaa0-7258-93cc-7d7d2f5cefc6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxAuthorityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_019c766a-aaa0-7c03-974c-f3ce5f6f397e" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_019c766a-aaa0-7258-93cc-7d7d2f5cefc6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DomesticCountryMember_019c766a-aaa0-7330-8a91-cfe84cfd955f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DomesticCountryMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_019c766a-aaa0-7258-93cc-7d7d2f5cefc6" xlink:to="loc_us-gaap_DomesticCountryMember_019c766a-aaa0-7330-8a91-cfe84cfd955f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_stpr_CA_019c766a-aaa0-7c60-91e2-01755fef4a8b" xlink:href="https://xbrl.sec.gov/stpr/2025/stpr-2025.xsd#stpr_CA"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_019c766a-aaa0-7258-93cc-7d7d2f5cefc6" xlink:to="loc_stpr_CA_019c766a-aaa0-7c60-91e2-01755fef4a8b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_NewYorkCityMember_019c766a-aaa0-749a-9f3a-6b77bcf0a84c" xlink:href="hood-20251231.xsd#hood_NewYorkCityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_019c766a-aaa0-7258-93cc-7d7d2f5cefc6" xlink:to="loc_hood_NewYorkCityMember_019c766a-aaa0-749a-9f3a-6b77bcf0a84c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StateAndLocalJurisdictionMember_019c766a-aaa0-7c5a-9a37-c6767d87dce3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StateAndLocalJurisdictionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_019c766a-aaa0-7258-93cc-7d7d2f5cefc6" xlink:to="loc_us-gaap_StateAndLocalJurisdictionMember_019c766a-aaa0-7c5a-9a37-c6767d87dce3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignCountryMember_019c766a-aaa0-7390-b9f4-35b4068ef63b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ForeignCountryMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_019c766a-aaa0-7258-93cc-7d7d2f5cefc6" xlink:to="loc_us-gaap_ForeignCountryMember_019c766a-aaa0-7390-b9f4-35b4068ef63b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxesPaid_019c766a-aaa0-7983-99da-9436ca901336" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxesPaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_019c766a-aaa0-72a4-807b-353705985cca" xlink:to="loc_us-gaap_IncomeTaxesPaid_019c766a-aaa0-7983-99da-9436ca901336" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount_019c766a-aaa0-72fa-b748-106dce6f4941" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_019c766a-aaa0-72a4-807b-353705985cca" xlink:to="loc_us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount_019c766a-aaa0-72fa-b748-106dce6f4941" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwards_019c766a-aaa0-72d7-99d9-243fe8dec987" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLossCarryforwards"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_019c766a-aaa0-72a4-807b-353705985cca" xlink:to="loc_us-gaap_OperatingLossCarryforwards_019c766a-aaa0-72d7-99d9-243fe8dec987" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_TaxCreditCarryforwardSubjectToExpirationAmount_019c766a-aaa0-7fc4-9a43-6adcb5a140fb" xlink:href="hood-20251231.xsd#hood_TaxCreditCarryforwardSubjectToExpirationAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_019c766a-aaa0-72a4-807b-353705985cca" xlink:to="loc_hood_TaxCreditCarryforwardSubjectToExpirationAmount_019c766a-aaa0-7fc4-9a43-6adcb5a140fb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxCreditCarryforwardAmount_019c766a-aaa0-7240-b743-a25f75353dbf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TaxCreditCarryforwardAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_019c766a-aaa0-72a4-807b-353705985cca" xlink:to="loc_us-gaap_TaxCreditCarryforwardAmount_019c766a-aaa0-7240-b743-a25f75353dbf" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecognizedTaxBenefits_019c766a-aaa0-7f6d-9028-32ac75ba6a5e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_UnrecognizedTaxBenefits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_019c766a-aaa0-72a4-807b-353705985cca" xlink:to="loc_us-gaap_UnrecognizedTaxBenefits_019c766a-aaa0-7f6d-9028-32ac75ba6a5e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate_019c766a-aaa0-7b96-b7ad-4d76a2ccecd1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_019c766a-aaa0-72a4-807b-353705985cca" xlink:to="loc_us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate_019c766a-aaa0-7b96-b7ad-4d76a2ccecd1" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_UnrecognizedTaxBenefitsThatWouldNotImpactEffectiveTaxRate_019c766a-aaa0-7b40-85ce-83b6fc8280ca" xlink:href="hood-20251231.xsd#hood_UnrecognizedTaxBenefitsThatWouldNotImpactEffectiveTaxRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_019c766a-aaa0-72a4-807b-353705985cca" xlink:to="loc_hood_UnrecognizedTaxBenefitsThatWouldNotImpactEffectiveTaxRate_019c766a-aaa0-7b40-85ce-83b6fc8280ca" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued_019c766a-aaa0-7129-b0bc-844afe692eb3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_019c766a-aaa0-72a4-807b-353705985cca" xlink:to="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued_019c766a-aaa0-7129-b0bc-844afe692eb3" xlink:type="arc" order="8"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/PROPERTYSOFTWAREANDEQUIPMENTNETScheduleOfPropertySoftwareandEquipmentDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#PROPERTYSOFTWAREANDEQUIPMENTNETScheduleOfPropertySoftwareandEquipmentDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/PROPERTYSOFTWAREANDEQUIPMENTNETScheduleOfPropertySoftwareandEquipmentDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019c766a-aaa0-7407-881a-bf477850d0a5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019c766a-aaa0-7dd2-a8c1-c946504bb2f3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019c766a-aaa0-7407-881a-bf477850d0a5" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019c766a-aaa0-7dd2-a8c1-c946504bb2f3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019c766a-aaa0-784a-bf7d-de4b1158fbe1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019c766a-aaa0-7dd2-a8c1-c946504bb2f3" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019c766a-aaa0-784a-bf7d-de4b1158fbe1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019c766a-aaa0-784a-bf7d-de4b1158fbe1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019c766a-aaa0-784a-bf7d-de4b1158fbe1" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019c766a-aaa0-784a-bf7d-de4b1158fbe1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019c766a-aaa0-7e7e-bbcf-24d0f4a059f0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019c766a-aaa0-784a-bf7d-de4b1158fbe1" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019c766a-aaa0-7e7e-bbcf-24d0f4a059f0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SoftwareDevelopmentMember_019c766a-aaa0-723f-a5e3-20a000dadb98" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SoftwareDevelopmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019c766a-aaa0-7e7e-bbcf-24d0f4a059f0" xlink:to="loc_us-gaap_SoftwareDevelopmentMember_019c766a-aaa0-723f-a5e3-20a000dadb98" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseholdImprovementsMember_019c766a-aaa0-78d8-9844-d70c06a84db7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LeaseholdImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019c766a-aaa0-7e7e-bbcf-24d0f4a059f0" xlink:to="loc_us-gaap_LeaseholdImprovementsMember_019c766a-aaa0-78d8-9844-d70c06a84db7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComputerEquipmentMember_019c766a-aaa0-79d7-a4a2-22ec04995040" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ComputerEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019c766a-aaa0-7e7e-bbcf-24d0f4a059f0" xlink:to="loc_us-gaap_ComputerEquipmentMember_019c766a-aaa0-79d7-a4a2-22ec04995040" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FurnitureAndFixturesMember_019c766a-aaa0-7836-a05e-22fe2c81cf87" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FurnitureAndFixturesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019c766a-aaa0-7e7e-bbcf-24d0f4a059f0" xlink:to="loc_us-gaap_FurnitureAndFixturesMember_019c766a-aaa0-7836-a05e-22fe2c81cf87" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionInProgressMember_019c766a-aaa0-7926-966c-340340ad6989" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConstructionInProgressMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019c766a-aaa0-7e7e-bbcf-24d0f4a059f0" xlink:to="loc_us-gaap_ConstructionInProgressMember_019c766a-aaa0-7926-966c-340340ad6989" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_019c766a-aaa0-72d6-a346-7723a13774a0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019c766a-aaa0-7407-881a-bf477850d0a5" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_019c766a-aaa0-72d6-a346-7723a13774a0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_019c766a-aaa0-7708-8f6e-b37bd647be28" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019c766a-aaa0-7407-881a-bf477850d0a5" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_019c766a-aaa0-7708-8f6e-b37bd647be28" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_019c766a-aaa0-7058-a9eb-9ac6dd388198" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019c766a-aaa0-7407-881a-bf477850d0a5" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_019c766a-aaa0-7058-a9eb-9ac6dd388198" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/SECURITIESBORROWINGANDLENDINGNarrativeDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#SECURITIESBORROWINGANDLENDINGNarrativeDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/SECURITIESBORROWINGANDLENDINGNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OffsettingAssetsLineItems_019c766a-aaa0-7736-9e11-d2af769d860c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OffsettingAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OffsettingAssetsTable_019c766a-aaa0-7780-beb3-1507f23882c4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OffsettingAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_OffsettingAssetsLineItems_019c766a-aaa0-7736-9e11-d2af769d860c" xlink:to="loc_us-gaap_OffsettingAssetsTable_019c766a-aaa0-7780-beb3-1507f23882c4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PledgedStatusAxis_019c766a-aaa0-74bd-bd85-ae91d8c6dab4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PledgedStatusAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_OffsettingAssetsTable_019c766a-aaa0-7780-beb3-1507f23882c4" xlink:to="loc_us-gaap_PledgedStatusAxis_019c766a-aaa0-74bd-bd85-ae91d8c6dab4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PledgedStatusDomain_019c766a-aaa0-74bd-bd85-ae91d8c6dab4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PledgedStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PledgedStatusAxis_019c766a-aaa0-74bd-bd85-ae91d8c6dab4" xlink:to="loc_us-gaap_PledgedStatusDomain_019c766a-aaa0-74bd-bd85-ae91d8c6dab4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PledgedStatusDomain_019c766a-aaa0-744a-a761-2b71b66ee018" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PledgedStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PledgedStatusAxis_019c766a-aaa0-74bd-bd85-ae91d8c6dab4" xlink:to="loc_us-gaap_PledgedStatusDomain_019c766a-aaa0-744a-a761-2b71b66ee018" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetPledgedAsCollateralMember_019c766a-aaa0-7685-bde9-87f54bfd1753" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetPledgedAsCollateralMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PledgedStatusDomain_019c766a-aaa0-744a-a761-2b71b66ee018" xlink:to="loc_us-gaap_AssetPledgedAsCollateralMember_019c766a-aaa0-7685-bde9-87f54bfd1753" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PledgingPurposeAxis_019c766a-aaa0-77d3-8cfb-85e8abbcd020" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PledgingPurposeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_OffsettingAssetsTable_019c766a-aaa0-7780-beb3-1507f23882c4" xlink:to="loc_us-gaap_PledgingPurposeAxis_019c766a-aaa0-77d3-8cfb-85e8abbcd020" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PledgingPurposeDomain_019c766a-aaa0-77d3-8cfb-85e8abbcd020_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PledgingPurposeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PledgingPurposeAxis_019c766a-aaa0-77d3-8cfb-85e8abbcd020" xlink:to="loc_us-gaap_PledgingPurposeDomain_019c766a-aaa0-77d3-8cfb-85e8abbcd020_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PledgingPurposeDomain_019c766a-aaa0-7edf-98a6-8632dea92f09" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PledgingPurposeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PledgingPurposeAxis_019c766a-aaa0-77d3-8cfb-85e8abbcd020" xlink:to="loc_us-gaap_PledgingPurposeDomain_019c766a-aaa0-7edf-98a6-8632dea92f09" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseMember_019c766a-aaa0-7e6a-b6ff-c1b2bebbac16" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PledgingPurposeDomain_019c766a-aaa0-7edf-98a6-8632dea92f09" xlink:to="loc_us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseMember_019c766a-aaa0-7e6a-b6ff-c1b2bebbac16" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentsOwnedAtFairValue_019c766a-aaa0-77ff-b6cc-59db42ae4f21" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancialInstrumentsOwnedAtFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OffsettingAssetsLineItems_019c766a-aaa0-7736-9e11-d2af769d860c" xlink:to="loc_us-gaap_FinancialInstrumentsOwnedAtFairValue_019c766a-aaa0-77ff-b6cc-59db42ae4f21" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuritiesBorrowedCollateralObligationToReturnCash_019c766a-aaa0-704d-aba2-981509f9e352" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SecuritiesBorrowedCollateralObligationToReturnCash"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OffsettingAssetsLineItems_019c766a-aaa0-7736-9e11-d2af769d860c" xlink:to="loc_us-gaap_SecuritiesBorrowedCollateralObligationToReturnCash_019c766a-aaa0-704d-aba2-981509f9e352" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuritiesLoanedCollateralRightToReclaimCash_019c766a-aaa0-7ed6-97aa-180b231dcb28" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SecuritiesLoanedCollateralRightToReclaimCash"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OffsettingAssetsLineItems_019c766a-aaa0-7736-9e11-d2af769d860c" xlink:to="loc_us-gaap_SecuritiesLoanedCollateralRightToReclaimCash_019c766a-aaa0-7ed6-97aa-180b231dcb28" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_PledgedAssetsSeparatelyReportedSecuritiesPledgedAsCollateralWithClearingOrganizations_019c766a-aaa0-7ad4-b047-a83a646a0acc" xlink:href="hood-20251231.xsd#hood_PledgedAssetsSeparatelyReportedSecuritiesPledgedAsCollateralWithClearingOrganizations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OffsettingAssetsLineItems_019c766a-aaa0-7736-9e11-d2af769d860c" xlink:to="loc_hood_PledgedAssetsSeparatelyReportedSecuritiesPledgedAsCollateralWithClearingOrganizations_019c766a-aaa0-7ad4-b047-a83a646a0acc" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/FINANCINGACTIVITIESANDOFFBALANCESHEETRISKDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#FINANCINGACTIVITIESANDOFFBALANCESHEETRISKDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/FINANCINGACTIVITIESANDOFFBALANCESHEETRISKDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_019c766a-aaa0-795e-b219-fd64361b8f6b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_019c766a-aaa0-7ea8-94ef-d691eef448e2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019c766a-aaa0-795e-b219-fd64361b8f6b" xlink:to="loc_us-gaap_DebtInstrumentTable_019c766a-aaa0-7ea8-94ef-d691eef448e2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_019c766a-aaa0-7334-9fe6-7cedb0dfa658" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019c766a-aaa0-7ea8-94ef-d691eef448e2" xlink:to="loc_us-gaap_CreditFacilityAxis_019c766a-aaa0-7334-9fe6-7cedb0dfa658" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_019c766a-aaa0-7334-9fe6-7cedb0dfa658_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_019c766a-aaa0-7334-9fe6-7cedb0dfa658" xlink:to="loc_us-gaap_CreditFacilityDomain_019c766a-aaa0-7334-9fe6-7cedb0dfa658_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_019c766a-aaa0-74cc-82a7-f1b95f09c5fb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_019c766a-aaa0-7334-9fe6-7cedb0dfa658" xlink:to="loc_us-gaap_CreditFacilityDomain_019c766a-aaa0-74cc-82a7-f1b95f09c5fb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_019c766a-aaa0-7208-a00c-118b5806f2e3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_019c766a-aaa0-74cc-82a7-f1b95f09c5fb" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_019c766a-aaa0-7208-a00c-118b5806f2e3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_019c766a-aaa0-7ac8-af52-8e451d08be22" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019c766a-aaa0-7ea8-94ef-d691eef448e2" xlink:to="loc_us-gaap_DebtInstrumentAxis_019c766a-aaa0-7ac8-af52-8e451d08be22" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019c766a-aaa0-7ac8-af52-8e451d08be22_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_019c766a-aaa0-7ac8-af52-8e451d08be22" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019c766a-aaa0-7ac8-af52-8e451d08be22_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_019c766a-aaa0-72ae-b907-248881eec37c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_019c766a-aaa0-7ac8-af52-8e451d08be22" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_019c766a-aaa0-72ae-b907-248881eec37c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_RHMMarch2025CreditAgreementMember_019c766a-aaa0-770c-ba88-d4d6e2aa0b44" xlink:href="hood-20251231.xsd#hood_RHMMarch2025CreditAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019c766a-aaa0-72ae-b907-248881eec37c" xlink:to="loc_hood_RHMMarch2025CreditAgreementMember_019c766a-aaa0-770c-ba88-d4d6e2aa0b44" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_RHSMarch2025CreditAgreementMember_019c766a-aaa0-7beb-9575-7a3f362ce23e" xlink:href="hood-20251231.xsd#hood_RHSMarch2025CreditAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019c766a-aaa0-72ae-b907-248881eec37c" xlink:to="loc_hood_RHSMarch2025CreditAgreementMember_019c766a-aaa0-7beb-9575-7a3f362ce23e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_RHSMarch2025CreditAgreementTrancheAMember_019c766a-aaa0-7cff-863c-4335ac68d30c" xlink:href="hood-20251231.xsd#hood_RHSMarch2025CreditAgreementTrancheAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019c766a-aaa0-72ae-b907-248881eec37c" xlink:to="loc_hood_RHSMarch2025CreditAgreementTrancheAMember_019c766a-aaa0-7cff-863c-4335ac68d30c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_RHMMarch2025CreditFacilityTrancheBAndCMember_019c766a-aaa0-7b42-a7a2-e5361de64082" xlink:href="hood-20251231.xsd#hood_RHMMarch2025CreditFacilityTrancheBAndCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019c766a-aaa0-72ae-b907-248881eec37c" xlink:to="loc_hood_RHMMarch2025CreditFacilityTrancheBAndCMember_019c766a-aaa0-7b42-a7a2-e5361de64082" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_RHSMarch2024CreditAgreementMember_019c766a-aaa0-7821-825f-3bcc92b41d26" xlink:href="hood-20251231.xsd#hood_RHSMarch2024CreditAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019c766a-aaa0-72ae-b907-248881eec37c" xlink:to="loc_hood_RHSMarch2024CreditAgreementMember_019c766a-aaa0-7821-825f-3bcc92b41d26" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_BarclaysArrangementMaturingNovember2026Member_019c766a-aaa0-7b03-b9c6-472a359df189" xlink:href="hood-20251231.xsd#hood_BarclaysArrangementMaturingNovember2026Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019c766a-aaa0-72ae-b907-248881eec37c" xlink:to="loc_hood_BarclaysArrangementMaturingNovember2026Member_019c766a-aaa0-7b03-b9c6-472a359df189" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_SVBArrangementMaturingApril2027Member_019c766a-aaa0-764a-b8db-ccef4135d738" xlink:href="hood-20251231.xsd#hood_SVBArrangementMaturingApril2027Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019c766a-aaa0-72ae-b907-248881eec37c" xlink:to="loc_hood_SVBArrangementMaturingApril2027Member_019c766a-aaa0-764a-b8db-ccef4135d738" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_WellsFargoBankArrangementMaturingAugust2028Member_019c766a-aaa0-7846-b113-7ee4bc05aa16" xlink:href="hood-20251231.xsd#hood_WellsFargoBankArrangementMaturingAugust2028Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019c766a-aaa0-72ae-b907-248881eec37c" xlink:to="loc_hood_WellsFargoBankArrangementMaturingAugust2028Member_019c766a-aaa0-7846-b113-7ee4bc05aa16" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_TruistBankArrangementMaturingAugust2028Member_019c766a-aaa0-7d71-9413-dd2ae92be7eb" xlink:href="hood-20251231.xsd#hood_TruistBankArrangementMaturingAugust2028Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019c766a-aaa0-72ae-b907-248881eec37c" xlink:to="loc_hood_TruistBankArrangementMaturingAugust2028Member_019c766a-aaa0-7d71-9413-dd2ae92be7eb" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_TruistBankArrangementMaturingNovember2028Member_019c766a-aaa0-77ad-a08b-f16e5dbc684b" xlink:href="hood-20251231.xsd#hood_TruistBankArrangementMaturingNovember2028Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019c766a-aaa0-72ae-b907-248881eec37c" xlink:to="loc_hood_TruistBankArrangementMaturingNovember2028Member_019c766a-aaa0-77ad-a08b-f16e5dbc684b" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_SVBAndBarclaysArragementsMember_019c766a-aaa0-7554-86a5-a50c5ee846f7" xlink:href="hood-20251231.xsd#hood_SVBAndBarclaysArragementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019c766a-aaa0-72ae-b907-248881eec37c" xlink:to="loc_hood_SVBAndBarclaysArragementsMember_019c766a-aaa0-7554-86a5-a50c5ee846f7" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_SVBBarclaysAndWFArrangementsMember_019c766a-aaa0-7a19-a91f-e226986bd78b" xlink:href="hood-20251231.xsd#hood_SVBBarclaysAndWFArrangementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_019c766a-aaa0-72ae-b907-248881eec37c" xlink:to="loc_hood_SVBBarclaysAndWFArrangementsMember_019c766a-aaa0-7a19-a91f-e226986bd78b" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019c766a-aaa0-7f93-b4b0-2eea9b89c917" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019c766a-aaa0-7ea8-94ef-d691eef448e2" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019c766a-aaa0-7f93-b4b0-2eea9b89c917" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019c766a-aaa0-7f93-b4b0-2eea9b89c917_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019c766a-aaa0-7f93-b4b0-2eea9b89c917" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019c766a-aaa0-7f93-b4b0-2eea9b89c917_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019c766a-aaa0-7cf9-a99d-aeae31015805" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019c766a-aaa0-7f93-b4b0-2eea9b89c917" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019c766a-aaa0-7cf9-a99d-aeae31015805" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_019c766a-aaa0-7cf6-a5da-b09b15d068d6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019c766a-aaa0-7cf9-a99d-aeae31015805" xlink:to="loc_us-gaap_LineOfCreditMember_019c766a-aaa0-7cf6-a5da-b09b15d068d6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_019c766a-aaa0-79a6-84b0-d0422379fa5b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VariableRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019c766a-aaa0-7ea8-94ef-d691eef448e2" xlink:to="loc_us-gaap_VariableRateAxis_019c766a-aaa0-79a6-84b0-d0422379fa5b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_019c766a-aaa0-79a6-84b0-d0422379fa5b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_019c766a-aaa0-79a6-84b0-d0422379fa5b" xlink:to="loc_us-gaap_VariableRateDomain_019c766a-aaa0-79a6-84b0-d0422379fa5b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_019c766a-aaa0-701f-9aae-b9c53fa40a87" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_019c766a-aaa0-79a6-84b0-d0422379fa5b" xlink:to="loc_us-gaap_VariableRateDomain_019c766a-aaa0-701f-9aae-b9c53fa40a87" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_FederalReserveBankOfNewYorkRateMember_019c766a-aaa0-7aab-a1a5-38f75ad0be30" xlink:href="hood-20251231.xsd#hood_FederalReserveBankOfNewYorkRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_019c766a-aaa0-701f-9aae-b9c53fa40a87" xlink:to="loc_hood_FederalReserveBankOfNewYorkRateMember_019c766a-aaa0-7aab-a1a5-38f75ad0be30" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredOvernightFinancingRateSofrMember_019c766a-aaa0-7fe4-88f7-e502302c50fb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SecuredOvernightFinancingRateSofrMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_019c766a-aaa0-701f-9aae-b9c53fa40a87" xlink:to="loc_us-gaap_SecuredOvernightFinancingRateSofrMember_019c766a-aaa0-7fe4-88f7-e502302c50fb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_SecuredOvernightFinancingRateInterestPeriodOfOneMonthMember_019c766a-aaa0-703b-bd8c-849a3c214880" xlink:href="hood-20251231.xsd#hood_SecuredOvernightFinancingRateInterestPeriodOfOneMonthMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_019c766a-aaa0-701f-9aae-b9c53fa40a87" xlink:to="loc_hood_SecuredOvernightFinancingRateInterestPeriodOfOneMonthMember_019c766a-aaa0-703b-bd8c-849a3c214880" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BaseRateMember_019c766a-aaa0-76ad-85de-032369baf643" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BaseRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_019c766a-aaa0-701f-9aae-b9c53fa40a87" xlink:to="loc_us-gaap_BaseRateMember_019c766a-aaa0-76ad-85de-032369baf643" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_CommercialPaperRateMember_019c766a-aaa0-7e38-88ab-60543eddd959" xlink:href="hood-20251231.xsd#hood_CommercialPaperRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_019c766a-aaa0-701f-9aae-b9c53fa40a87" xlink:to="loc_hood_CommercialPaperRateMember_019c766a-aaa0-7e38-88ab-60543eddd959" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_DailySimpleSOFRMember_019c766a-aaa0-7864-a70a-082d9ed72c5f" xlink:href="hood-20251231.xsd#hood_DailySimpleSOFRMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_019c766a-aaa0-701f-9aae-b9c53fa40a87" xlink:to="loc_hood_DailySimpleSOFRMember_019c766a-aaa0-7864-a70a-082d9ed72c5f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_DailySimpleSOFRDuringControlledOrEarlyAmortizationPeriodMember_019c766a-aaa0-7f3a-945d-6b1c640d44f0" xlink:href="hood-20251231.xsd#hood_DailySimpleSOFRDuringControlledOrEarlyAmortizationPeriodMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_019c766a-aaa0-701f-9aae-b9c53fa40a87" xlink:to="loc_hood_DailySimpleSOFRDuringControlledOrEarlyAmortizationPeriodMember_019c766a-aaa0-7f3a-945d-6b1c640d44f0" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_019c766a-aaa0-7a76-bd2f-417f892d1abe" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019c766a-aaa0-7ea8-94ef-d691eef448e2" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_019c766a-aaa0-7a76-bd2f-417f892d1abe" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_019c766a-aaa0-7a76-bd2f-417f892d1abe_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_019c766a-aaa0-7a76-bd2f-417f892d1abe" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_019c766a-aaa0-7a76-bd2f-417f892d1abe_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_019c766a-aaa0-7b58-9f84-d3b08e0adade" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_019c766a-aaa0-7a76-bd2f-417f892d1abe" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_019c766a-aaa0-7b58-9f84-d3b08e0adade" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_March2025CreditFacilityMember_019c766a-aaa0-7ed0-8e28-207c1630ec57" xlink:href="hood-20251231.xsd#hood_March2025CreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_019c766a-aaa0-7b58-9f84-d3b08e0adade" xlink:to="loc_hood_March2025CreditFacilityMember_019c766a-aaa0-7ed0-8e28-207c1630ec57" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_019c766a-aaa0-7bb1-b0b4-42749713622b" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019c766a-aaa0-7ea8-94ef-d691eef448e2" xlink:to="loc_srt_ConsolidatedEntitiesAxis_019c766a-aaa0-7bb1-b0b4-42749713622b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_019c766a-aaa0-7bb1-b0b4-42749713622b_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_019c766a-aaa0-7bb1-b0b4-42749713622b" xlink:to="loc_srt_ConsolidatedEntitiesDomain_019c766a-aaa0-7bb1-b0b4-42749713622b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_019c766a-aaa0-7b62-a741-d67e0ffba2e9" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_019c766a-aaa0-7bb1-b0b4-42749713622b" xlink:to="loc_srt_ConsolidatedEntitiesDomain_019c766a-aaa0-7b62-a741-d67e0ffba2e9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableInterestEntityPrimaryBeneficiaryMember_019c766a-aaa0-7df7-b2a2-cad21b2a4c5a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VariableInterestEntityPrimaryBeneficiaryMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_019c766a-aaa0-7b62-a741-d67e0ffba2e9" xlink:to="loc_us-gaap_VariableInterestEntityPrimaryBeneficiaryMember_019c766a-aaa0-7df7-b2a2-cad21b2a4c5a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019c766a-aaa0-7194-ba44-e66dc3968b6a" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019c766a-aaa0-7ea8-94ef-d691eef448e2" xlink:to="loc_srt_RangeAxis_019c766a-aaa0-7194-ba44-e66dc3968b6a" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019c766a-aaa0-7194-ba44-e66dc3968b6a_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019c766a-aaa0-7194-ba44-e66dc3968b6a" xlink:to="loc_srt_RangeMember_019c766a-aaa0-7194-ba44-e66dc3968b6a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019c766a-aaa0-7a91-a525-e4de3e3bac00" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019c766a-aaa0-7194-ba44-e66dc3968b6a" xlink:to="loc_srt_RangeMember_019c766a-aaa0-7a91-a525-e4de3e3bac00" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019c766a-aaa0-718f-bdfd-38945c230374" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019c766a-aaa0-7a91-a525-e4de3e3bac00" xlink:to="loc_srt_MinimumMember_019c766a-aaa0-718f-bdfd-38945c230374" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019c766a-aaa0-7538-83d3-2fd7e346a277" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019c766a-aaa0-7a91-a525-e4de3e3bac00" xlink:to="loc_srt_MaximumMember_019c766a-aaa0-7538-83d3-2fd7e346a277" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_LineOfCreditConditionAxis_019c766a-aaa0-7b40-8ccb-c331f3bc0632" xlink:href="hood-20251231.xsd#hood_LineOfCreditConditionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019c766a-aaa0-7ea8-94ef-d691eef448e2" xlink:to="loc_hood_LineOfCreditConditionAxis_019c766a-aaa0-7b40-8ccb-c331f3bc0632" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_LineOfCreditConditionDomain_019c766a-aaa0-7b40-8ccb-c331f3bc0632_default" xlink:href="hood-20251231.xsd#hood_LineOfCreditConditionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_hood_LineOfCreditConditionAxis_019c766a-aaa0-7b40-8ccb-c331f3bc0632" xlink:to="loc_hood_LineOfCreditConditionDomain_019c766a-aaa0-7b40-8ccb-c331f3bc0632_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_LineOfCreditConditionDomain_019c766a-aaa0-7bad-8f12-744820b4c888" xlink:href="hood-20251231.xsd#hood_LineOfCreditConditionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_hood_LineOfCreditConditionAxis_019c766a-aaa0-7b40-8ccb-c331f3bc0632" xlink:to="loc_hood_LineOfCreditConditionDomain_019c766a-aaa0-7bad-8f12-744820b4c888" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_GreaterThan50MillionMember_019c766a-aaa0-7626-a3e7-48e6400a3073" xlink:href="hood-20251231.xsd#hood_GreaterThan50MillionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hood_LineOfCreditConditionDomain_019c766a-aaa0-7bad-8f12-744820b4c888" xlink:to="loc_hood_GreaterThan50MillionMember_019c766a-aaa0-7626-a3e7-48e6400a3073" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_019c766a-aaa0-739e-be41-73ec57ee9566" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019c766a-aaa0-7ea8-94ef-d691eef448e2" xlink:to="loc_srt_CounterpartyNameAxis_019c766a-aaa0-739e-be41-73ec57ee9566" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019c766a-aaa0-739e-be41-73ec57ee9566_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_019c766a-aaa0-739e-be41-73ec57ee9566" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019c766a-aaa0-739e-be41-73ec57ee9566_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019c766a-aaa0-7212-89fd-ef6db588a303" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_019c766a-aaa0-739e-be41-73ec57ee9566" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019c766a-aaa0-7212-89fd-ef6db588a303" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_CoastalBankMember_019c766a-aaa0-7207-8441-4c84eee25360" xlink:href="hood-20251231.xsd#hood_CoastalBankMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_019c766a-aaa0-7212-89fd-ef6db588a303" xlink:to="loc_hood_CoastalBankMember_019c766a-aaa0-7207-8441-4c84eee25360" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_019c766a-aaa0-796c-9638-20ac630358de" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019c766a-aaa0-7ea8-94ef-d691eef448e2" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_019c766a-aaa0-796c-9638-20ac630358de" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aaa0-796c-9638-20ac630358de_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019c766a-aaa0-796c-9638-20ac630358de" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aaa0-796c-9638-20ac630358de_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aaa0-7340-856d-34a9c0483570" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019c766a-aaa0-796c-9638-20ac630358de" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aaa0-7340-856d-34a9c0483570" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_RobinhoodCreditMember_019c766a-aaa0-7540-8302-4aaa984f5bbe" xlink:href="hood-20251231.xsd#hood_RobinhoodCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-aaa0-7340-856d-34a9c0483570" xlink:to="loc_hood_RobinhoodCreditMember_019c766a-aaa0-7540-8302-4aaa984f5bbe" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_ProgramAgreementInterestRateMarginAxis_019c766a-aaa0-74fe-8fdd-60b9bad39f76" xlink:href="hood-20251231.xsd#hood_ProgramAgreementInterestRateMarginAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019c766a-aaa0-7ea8-94ef-d691eef448e2" xlink:to="loc_hood_ProgramAgreementInterestRateMarginAxis_019c766a-aaa0-74fe-8fdd-60b9bad39f76" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_ProgramAgreementInterestRateMarginDomain_019c766a-aaa0-74fe-8fdd-60b9bad39f76_default" xlink:href="hood-20251231.xsd#hood_ProgramAgreementInterestRateMarginDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_hood_ProgramAgreementInterestRateMarginAxis_019c766a-aaa0-74fe-8fdd-60b9bad39f76" xlink:to="loc_hood_ProgramAgreementInterestRateMarginDomain_019c766a-aaa0-74fe-8fdd-60b9bad39f76_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_ProgramAgreementInterestRateMarginDomain_019c766a-aaa0-7890-ac75-9a244268fedd" xlink:href="hood-20251231.xsd#hood_ProgramAgreementInterestRateMarginDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_hood_ProgramAgreementInterestRateMarginAxis_019c766a-aaa0-74fe-8fdd-60b9bad39f76" xlink:to="loc_hood_ProgramAgreementInterestRateMarginDomain_019c766a-aaa0-7890-ac75-9a244268fedd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_InterestRateMarginOneMember_019c766a-aaa0-78d7-af65-c646bb6ca662" xlink:href="hood-20251231.xsd#hood_InterestRateMarginOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hood_ProgramAgreementInterestRateMarginDomain_019c766a-aaa0-7890-ac75-9a244268fedd" xlink:to="loc_hood_InterestRateMarginOneMember_019c766a-aaa0-78d7-af65-c646bb6ca662" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_InterestRateMarginTwoMember_019c766a-aaa0-7e65-9070-27f78eb54cc5" xlink:href="hood-20251231.xsd#hood_InterestRateMarginTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hood_ProgramAgreementInterestRateMarginDomain_019c766a-aaa0-7890-ac75-9a244268fedd" xlink:to="loc_hood_InterestRateMarginTwoMember_019c766a-aaa0-7e65-9070-27f78eb54cc5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_019c766a-aaa0-7663-8ecf-71bd1a48675e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LossContingenciesByNatureOfContingencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019c766a-aaa0-7ea8-94ef-d691eef448e2" xlink:to="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_019c766a-aaa0-7663-8ecf-71bd1a48675e" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNatureDomain_019c766a-aaa0-7663-8ecf-71bd1a48675e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LossContingencyNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_019c766a-aaa0-7663-8ecf-71bd1a48675e" xlink:to="loc_us-gaap_LossContingencyNatureDomain_019c766a-aaa0-7663-8ecf-71bd1a48675e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNatureDomain_019c766a-aaa0-752d-8bfb-4bcb4a70f7be" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LossContingencyNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_019c766a-aaa0-7663-8ecf-71bd1a48675e" xlink:to="loc_us-gaap_LossContingencyNatureDomain_019c766a-aaa0-752d-8bfb-4bcb4a70f7be" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_RemoteMember_019c766a-aaa0-727f-ac83-ec86c1db7fe9" xlink:href="hood-20251231.xsd#hood_RemoteMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingencyNatureDomain_019c766a-aaa0-752d-8bfb-4bcb4a70f7be" xlink:to="loc_hood_RemoteMember_019c766a-aaa0-727f-ac83-ec86c1db7fe9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_019c766a-aaa0-75e8-bf92-7747e8f36a3d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019c766a-aaa0-795e-b219-fd64361b8f6b" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_019c766a-aaa0-75e8-bf92-7747e8f36a3d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_LineOfCreditFacilityIncreaseLimit_019c766a-aaa0-71c5-8681-be0e276dce30" xlink:href="hood-20251231.xsd#hood_LineOfCreditFacilityIncreaseLimit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019c766a-aaa0-795e-b219-fd64361b8f6b" xlink:to="loc_hood_LineOfCreditFacilityIncreaseLimit_019c766a-aaa0-71c5-8681-be0e276dce30" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_019c766a-aaa0-77d4-990d-167b31e7f3b9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019c766a-aaa0-795e-b219-fd64361b8f6b" xlink:to="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_019c766a-aaa0-77d4-990d-167b31e7f3b9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_019c766a-aaa0-765d-93bc-32ea89936ebc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019c766a-aaa0-795e-b219-fd64361b8f6b" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_019c766a-aaa0-765d-93bc-32ea89936ebc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_019c766a-aaa0-7688-9e4e-f8b12c6c0422" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityCommitmentFeePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019c766a-aaa0-795e-b219-fd64361b8f6b" xlink:to="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_019c766a-aaa0-7688-9e4e-f8b12c6c0422" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTerm_019c766a-aaa0-7d41-b1a9-06199ba52109" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019c766a-aaa0-795e-b219-fd64361b8f6b" xlink:to="loc_us-gaap_DebtInstrumentTerm_019c766a-aaa0-7d41-b1a9-06199ba52109" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCredit_019c766a-aaa0-7a69-b30f-491f76c0510d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019c766a-aaa0-795e-b219-fd64361b8f6b" xlink:to="loc_us-gaap_LineOfCredit_019c766a-aaa0-7a69-b30f-491f76c0510d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_019c766a-aaa0-799f-8311-116ac3dee2ff" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019c766a-aaa0-795e-b219-fd64361b8f6b" xlink:to="loc_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_019c766a-aaa0-799f-8311-116ac3dee2ff" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019c766a-aaa0-795c-9d25-ec893862508d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019c766a-aaa0-795e-b219-fd64361b8f6b" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019c766a-aaa0-795c-9d25-ec893862508d" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtWeightedAverageInterestRate_019c766a-aaa0-76e6-af09-0a5acac1ee1f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtWeightedAverageInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019c766a-aaa0-795e-b219-fd64361b8f6b" xlink:to="loc_us-gaap_DebtWeightedAverageInterestRate_019c766a-aaa0-76e6-af09-0a5acac1ee1f" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireReceivables_019c766a-aaa0-72e5-b6df-41168aadad63" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsToAcquireReceivables"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019c766a-aaa0-795e-b219-fd64361b8f6b" xlink:to="loc_us-gaap_PaymentsToAcquireReceivables_019c766a-aaa0-72e5-b6df-41168aadad63" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditAndDebitCardReceivablesAtCarryingValue_019c766a-aaa0-712a-9ca5-4db6ef900e59" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditAndDebitCardReceivablesAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019c766a-aaa0-795e-b219-fd64361b8f6b" xlink:to="loc_us-gaap_CreditAndDebitCardReceivablesAtCarryingValue_019c766a-aaa0-712a-9ca5-4db6ef900e59" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeExpenseNet_019c766a-aaa0-7d07-a8cc-5e996aa574a7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestIncomeExpenseNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019c766a-aaa0-795e-b219-fd64361b8f6b" xlink:to="loc_us-gaap_InterestIncomeExpenseNet_019c766a-aaa0-7d07-a8cc-5e996aa574a7" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_ProgramAgreementCustomerAdvanceLimit_019c766a-aaa0-7d92-8205-7c32138d8e98" xlink:href="hood-20251231.xsd#hood_ProgramAgreementCustomerAdvanceLimit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019c766a-aaa0-795e-b219-fd64361b8f6b" xlink:to="loc_hood_ProgramAgreementCustomerAdvanceLimit_019c766a-aaa0-7d92-8205-7c32138d8e98" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_ProgramAgreementCustomerAdvanceLimitThreshold_019c766a-aaa0-7780-8dc4-c067db62a184" xlink:href="hood-20251231.xsd#hood_ProgramAgreementCustomerAdvanceLimitThreshold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019c766a-aaa0-795e-b219-fd64361b8f6b" xlink:to="loc_hood_ProgramAgreementCustomerAdvanceLimitThreshold_019c766a-aaa0-7780-8dc4-c067db62a184" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_ProgramAgreementOutstandingAmount_019c766a-aaa0-7305-a4ce-6be81ff06c7f" xlink:href="hood-20251231.xsd#hood_ProgramAgreementOutstandingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019c766a-aaa0-795e-b219-fd64361b8f6b" xlink:to="loc_hood_ProgramAgreementOutstandingAmount_019c766a-aaa0-7305-a4ce-6be81ff06c7f" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CryptoAssetFairValue_019c766a-aaa0-707b-b97b-b1f97b5a01bd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CryptoAssetFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019c766a-aaa0-795e-b219-fd64361b8f6b" xlink:to="loc_us-gaap_CryptoAssetFairValue_019c766a-aaa0-707b-b97b-b1f97b5a01bd" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyAccrualAtCarryingValue_019c766a-aaa0-7a9f-99ef-9d90578ec849" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LossContingencyAccrualAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019c766a-aaa0-795e-b219-fd64361b8f6b" xlink:to="loc_us-gaap_LossContingencyAccrualAtCarryingValue_019c766a-aaa0-7a9f-99ef-9d90578ec849" xlink:type="arc" order="17"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/COMMONSTOCKANDSTOCKHOLDERSEQUITYPreferredStockandCommonStockDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#COMMONSTOCKANDSTOCKHOLDERSEQUITYPreferredStockandCommonStockDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/COMMONSTOCKANDSTOCKHOLDERSEQUITYPreferredStockandCommonStockDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-aaa0-75ac-9383-228b43493be7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019c766a-aaa0-71d5-bc54-12eed10d9ea3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-aaa0-75ac-9383-228b43493be7" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019c766a-aaa0-71d5-bc54-12eed10d9ea3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019c766a-aaa0-783b-b8fb-102a0e922806" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019c766a-aaa0-71d5-bc54-12eed10d9ea3" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019c766a-aaa0-783b-b8fb-102a0e922806" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019c766a-aaa0-783b-b8fb-102a0e922806_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019c766a-aaa0-783b-b8fb-102a0e922806" xlink:to="loc_us-gaap_ClassOfStockDomain_019c766a-aaa0-783b-b8fb-102a0e922806_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019c766a-aaa0-77e8-8d45-c0a44c3bb312" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019c766a-aaa0-783b-b8fb-102a0e922806" xlink:to="loc_us-gaap_ClassOfStockDomain_019c766a-aaa0-77e8-8d45-c0a44c3bb312" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_019c766a-aaa0-74d0-a2c9-8141121adc08" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonClassAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019c766a-aaa0-77e8-8d45-c0a44c3bb312" xlink:to="loc_us-gaap_CommonClassAMember_019c766a-aaa0-74d0-a2c9-8141121adc08" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassBMember_019c766a-aaa0-7b72-b8e7-df17197c0df2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonClassBMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019c766a-aaa0-77e8-8d45-c0a44c3bb312" xlink:to="loc_us-gaap_CommonClassBMember_019c766a-aaa0-7b72-b8e7-df17197c0df2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConversionOfStockByUniqueDescriptionAxis_019c766a-aaa0-74cc-84a6-cd7cbd9643ab" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConversionOfStockByUniqueDescriptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019c766a-aaa0-71d5-bc54-12eed10d9ea3" xlink:to="loc_us-gaap_ConversionOfStockByUniqueDescriptionAxis_019c766a-aaa0-74cc-84a6-cd7cbd9643ab" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConversionOfStockNameDomain_019c766a-aaa0-74cc-84a6-cd7cbd9643ab_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConversionOfStockNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConversionOfStockByUniqueDescriptionAxis_019c766a-aaa0-74cc-84a6-cd7cbd9643ab" xlink:to="loc_us-gaap_ConversionOfStockNameDomain_019c766a-aaa0-74cc-84a6-cd7cbd9643ab_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConversionOfStockNameDomain_019c766a-aaa0-77b7-bae2-ade4368fcea6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConversionOfStockNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConversionOfStockByUniqueDescriptionAxis_019c766a-aaa0-74cc-84a6-cd7cbd9643ab" xlink:to="loc_us-gaap_ConversionOfStockNameDomain_019c766a-aaa0-77b7-bae2-ade4368fcea6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_ConversionOfClassBCommonStockIntoClassACommonMember_019c766a-aaa0-7865-82af-c73f72aae0d4" xlink:href="hood-20251231.xsd#hood_ConversionOfClassBCommonStockIntoClassACommonMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConversionOfStockNameDomain_019c766a-aaa0-77b7-bae2-ade4368fcea6" xlink:to="loc_hood_ConversionOfClassBCommonStockIntoClassACommonMember_019c766a-aaa0-7865-82af-c73f72aae0d4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_ConversionOfClassCCommonStockIntoClassACommonMember_019c766a-aaa0-78bf-8cd9-61838204a777" xlink:href="hood-20251231.xsd#hood_ConversionOfClassCCommonStockIntoClassACommonMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConversionOfStockNameDomain_019c766a-aaa0-77b7-bae2-ade4368fcea6" xlink:to="loc_hood_ConversionOfClassCCommonStockIntoClassACommonMember_019c766a-aaa0-78bf-8cd9-61838204a777" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019c766a-aaa0-7933-9aa7-435227f2922a" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019c766a-aaa0-71d5-bc54-12eed10d9ea3" xlink:to="loc_srt_RangeAxis_019c766a-aaa0-7933-9aa7-435227f2922a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019c766a-aaa0-7933-9aa7-435227f2922a_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019c766a-aaa0-7933-9aa7-435227f2922a" xlink:to="loc_srt_RangeMember_019c766a-aaa0-7933-9aa7-435227f2922a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019c766a-aaa0-7e73-b543-97a9c471de5a" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019c766a-aaa0-7933-9aa7-435227f2922a" xlink:to="loc_srt_RangeMember_019c766a-aaa0-7e73-b543-97a9c471de5a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019c766a-aaa0-78ca-82e4-8549f563dc10" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019c766a-aaa0-7e73-b543-97a9c471de5a" xlink:to="loc_srt_MinimumMember_019c766a-aaa0-78ca-82e4-8549f563dc10" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019c766a-aaa0-7335-a2b6-e08c15cc6e4b" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019c766a-aaa0-7e73-b543-97a9c471de5a" xlink:to="loc_srt_MaximumMember_019c766a-aaa0-7335-a2b6-e08c15cc6e4b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesOutstanding_019c766a-aaa0-76f0-82b2-0f2d510840ff" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PreferredStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-aaa0-75ac-9383-228b43493be7" xlink:to="loc_us-gaap_PreferredStockSharesOutstanding_019c766a-aaa0-76f0-82b2-0f2d510840ff" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_NumberOfClassesCommonStock_019c766a-aaa0-71f7-9d96-1e0ddbfab63f" xlink:href="hood-20251231.xsd#hood_NumberOfClassesCommonStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-aaa0-75ac-9383-228b43493be7" xlink:to="loc_hood_NumberOfClassesCommonStock_019c766a-aaa0-71f7-9d96-1e0ddbfab63f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_CommonStockVotingRightsNumberOfVotes_019c766a-aaa0-785a-876f-d26e74689020" xlink:href="hood-20251231.xsd#hood_CommonStockVotingRightsNumberOfVotes"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-aaa0-75ac-9383-228b43493be7" xlink:to="loc_hood_CommonStockVotingRightsNumberOfVotes_019c766a-aaa0-785a-876f-d26e74689020" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_CommonStockConvertibleConversionRatio_019c766a-aaa0-741c-9067-3211a85ac6d4" xlink:href="hood-20251231.xsd#hood_CommonStockConvertibleConversionRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-aaa0-75ac-9383-228b43493be7" xlink:to="loc_hood_CommonStockConvertibleConversionRatio_019c766a-aaa0-741c-9067-3211a85ac6d4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_CommonStockConversionBasisOutstandingSharesPercentage_019c766a-aaa0-7d86-ad5d-3d172bc83533" xlink:href="hood-20251231.xsd#hood_CommonStockConversionBasisOutstandingSharesPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-aaa0-75ac-9383-228b43493be7" xlink:to="loc_hood_CommonStockConversionBasisOutstandingSharesPercentage_019c766a-aaa0-7d86-ad5d-3d172bc83533" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_CommonStockConversionBasisOutstandingSharesFixedDays_019c766a-aaa0-71cf-8721-e3b48e888ad4" xlink:href="hood-20251231.xsd#hood_CommonStockConversionBasisOutstandingSharesFixedDays"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-aaa0-75ac-9383-228b43493be7" xlink:to="loc_hood_CommonStockConversionBasisOutstandingSharesFixedDays_019c766a-aaa0-71cf-8721-e3b48e888ad4" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_CommonStockConversionBasisPercentageOfAggregateSharesOutstanding_019c766a-aaa0-78a3-82d1-ba9b99939e1b" xlink:href="hood-20251231.xsd#hood_CommonStockConversionBasisPercentageOfAggregateSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-aaa0-75ac-9383-228b43493be7" xlink:to="loc_hood_CommonStockConversionBasisPercentageOfAggregateSharesOutstanding_019c766a-aaa0-78a3-82d1-ba9b99939e1b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_CommonStockConversionBasisAggregateOutstandingSharesFixedDays_019c766a-aaa0-7f97-a8a6-f9740b83042e" xlink:href="hood-20251231.xsd#hood_CommonStockConversionBasisAggregateOutstandingSharesFixedDays"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-aaa0-75ac-9383-228b43493be7" xlink:to="loc_hood_CommonStockConversionBasisAggregateOutstandingSharesFixedDays_019c766a-aaa0-7f97-a8a6-f9740b83042e" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_CommonStockConversionBasisApprovalPeriodDeathOrTotalDisabilityOfFounders_019c766a-aaa0-7051-b554-fc1136f08768" xlink:href="hood-20251231.xsd#hood_CommonStockConversionBasisApprovalPeriodDeathOrTotalDisabilityOfFounders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-aaa0-75ac-9383-228b43493be7" xlink:to="loc_hood_CommonStockConversionBasisApprovalPeriodDeathOrTotalDisabilityOfFounders_019c766a-aaa0-7051-b554-fc1136f08768" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_CommonStockConversionBasisApprovalPeriodDelay_019c766a-aaa0-7602-9782-36a309689f3e" xlink:href="hood-20251231.xsd#hood_CommonStockConversionBasisApprovalPeriodDelay"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-aaa0-75ac-9383-228b43493be7" xlink:to="loc_hood_CommonStockConversionBasisApprovalPeriodDelay_019c766a-aaa0-7602-9782-36a309689f3e" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_CommonStockConversionBasisFinalConversionDate_019c766a-aaa0-7718-b19d-392843439397" xlink:href="hood-20251231.xsd#hood_CommonStockConversionBasisFinalConversionDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-aaa0-75ac-9383-228b43493be7" xlink:to="loc_hood_CommonStockConversionBasisFinalConversionDate_019c766a-aaa0-7718-b19d-392843439397" xlink:type="arc" order="10"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/COMMONSTOCKANDSTOCKHOLDERSEQUITYWarrantsDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#COMMONSTOCKANDSTOCKHOLDERSEQUITYWarrantsDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/COMMONSTOCKANDSTOCKHOLDERSEQUITYWarrantsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightLineItems_019c766a-aaa0-7eff-8687-1943495a4c2a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfWarrantOrRightLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightTable_019c766a-aaa0-7c18-bd8c-4f7859f78e2e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfWarrantOrRightTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_019c766a-aaa0-7eff-8687-1943495a4c2a" xlink:to="loc_us-gaap_ClassOfWarrantOrRightTable_019c766a-aaa0-7c18-bd8c-4f7859f78e2e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019c766a-aaa0-7f8b-96ce-80262c4f1ff2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ClassOfWarrantOrRightTable_019c766a-aaa0-7c18-bd8c-4f7859f78e2e" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019c766a-aaa0-7f8b-96ce-80262c4f1ff2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019c766a-aaa0-7f8b-96ce-80262c4f1ff2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019c766a-aaa0-7f8b-96ce-80262c4f1ff2" xlink:to="loc_us-gaap_ClassOfStockDomain_019c766a-aaa0-7f8b-96ce-80262c4f1ff2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019c766a-aaa0-7b71-bfed-16788cab4ace" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019c766a-aaa0-7f8b-96ce-80262c4f1ff2" xlink:to="loc_us-gaap_ClassOfStockDomain_019c766a-aaa0-7b71-bfed-16788cab4ace" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_019c766a-aaa0-709d-ac99-9c666642ddd0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonClassAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019c766a-aaa0-7b71-bfed-16788cab4ace" xlink:to="loc_us-gaap_CommonClassAMember_019c766a-aaa0-709d-ac99-9c666642ddd0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_019c766a-aaa0-777e-bed1-8de8762afe25" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_019c766a-aaa0-7eff-8687-1943495a4c2a" xlink:to="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_019c766a-aaa0-777e-bed1-8de8762afe25" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_019c766a-aaa0-7804-9e0e-8c11b353e9dd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_019c766a-aaa0-7eff-8687-1943495a4c2a" xlink:to="loc_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_019c766a-aaa0-7804-9e0e-8c11b353e9dd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_ClassOfWarrantOrRightExercised_019c766a-aaa0-7add-ab4d-d94077fbdd9c" xlink:href="hood-20251231.xsd#hood_ClassOfWarrantOrRightExercised"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_019c766a-aaa0-7eff-8687-1943495a4c2a" xlink:to="loc_hood_ClassOfWarrantOrRightExercised_019c766a-aaa0-7add-ab4d-d94077fbdd9c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesIssued_019c766a-aaa0-7f59-8264-a81fa482659c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_019c766a-aaa0-7eff-8687-1943495a4c2a" xlink:to="loc_us-gaap_SharesIssued_019c766a-aaa0-7f59-8264-a81fa482659c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WarrantsAndRightsOutstanding_019c766a-aaa0-7543-b406-c7c213bcc8dc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_WarrantsAndRightsOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_019c766a-aaa0-7eff-8687-1943495a4c2a" xlink:to="loc_us-gaap_WarrantsAndRightsOutstanding_019c766a-aaa0-7543-b406-c7c213bcc8dc" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/COMMONSTOCKANDSTOCKHOLDERSEQUITYShareRepurchasesDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#COMMONSTOCKANDSTOCKHOLDERSEQUITYShareRepurchasesDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/COMMONSTOCKANDSTOCKHOLDERSEQUITYShareRepurchasesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityClassOfTreasuryStockLineItems_019c766a-aaa0-7628-add4-feb587661559" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityClassOfTreasuryStockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfTreasuryStockTable_019c766a-aaa0-70d4-8612-a7fc27232a84" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfTreasuryStockTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EquityClassOfTreasuryStockLineItems_019c766a-aaa0-7628-add4-feb587661559" xlink:to="loc_us-gaap_ClassOfTreasuryStockTable_019c766a-aaa0-70d4-8612-a7fc27232a84" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019c766a-aaa0-7876-b157-f05df1b8963d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ClassOfTreasuryStockTable_019c766a-aaa0-70d4-8612-a7fc27232a84" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019c766a-aaa0-7876-b157-f05df1b8963d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019c766a-aaa0-7876-b157-f05df1b8963d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019c766a-aaa0-7876-b157-f05df1b8963d" xlink:to="loc_us-gaap_ClassOfStockDomain_019c766a-aaa0-7876-b157-f05df1b8963d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019c766a-aaa0-72b3-a443-91ae125e4b8f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019c766a-aaa0-7876-b157-f05df1b8963d" xlink:to="loc_us-gaap_ClassOfStockDomain_019c766a-aaa0-72b3-a443-91ae125e4b8f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_019c766a-aaa0-7ecc-ba5d-c7286082bf89" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonClassAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019c766a-aaa0-72b3-a443-91ae125e4b8f" xlink:to="loc_us-gaap_CommonClassAMember_019c766a-aaa0-7ecc-ba5d-c7286082bf89" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StockRepurchaseProgramAuthorizedAmount1_019c766a-aaa0-7742-b4e4-aadcfa77e5db" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_StockRepurchaseProgramAuthorizedAmount1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityClassOfTreasuryStockLineItems_019c766a-aaa0-7628-add4-feb587661559" xlink:to="loc_srt_StockRepurchaseProgramAuthorizedAmount1_019c766a-aaa0-7742-b4e4-aadcfa77e5db" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_ShareRepurchaseProgramIncreasedAuthorizedAmount_019c766a-aaa0-7aa4-862e-0c2450c26351" xlink:href="hood-20251231.xsd#hood_ShareRepurchaseProgramIncreasedAuthorizedAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityClassOfTreasuryStockLineItems_019c766a-aaa0-7628-add4-feb587661559" xlink:to="loc_hood_ShareRepurchaseProgramIncreasedAuthorizedAmount_019c766a-aaa0-7aa4-862e-0c2450c26351" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchaseProgramPeriodInForce1_019c766a-aaa0-7c55-8b05-088a741326bf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockRepurchaseProgramPeriodInForce1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityClassOfTreasuryStockLineItems_019c766a-aaa0-7628-add4-feb587661559" xlink:to="loc_us-gaap_StockRepurchaseProgramPeriodInForce1_019c766a-aaa0-7c55-8b05-088a741326bf" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodShares_019c766a-aaa0-78b3-98e9-fa57e7252eb3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockRepurchasedDuringPeriodShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityClassOfTreasuryStockLineItems_019c766a-aaa0-7628-add4-feb587661559" xlink:to="loc_us-gaap_StockRepurchasedDuringPeriodShares_019c766a-aaa0-78b3-98e9-fa57e7252eb3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForRepurchaseOfCommonStock_019c766a-aaa0-74c4-ad0f-bbf25cd075e1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsForRepurchaseOfCommonStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityClassOfTreasuryStockLineItems_019c766a-aaa0-7628-add4-feb587661559" xlink:to="loc_us-gaap_PaymentsForRepurchaseOfCommonStock_019c766a-aaa0-74c4-ad0f-bbf25cd075e1" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/COMMONSTOCKANDSTOCKHOLDERSEQUITYEquityIncentivePlansDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#COMMONSTOCKANDSTOCKHOLDERSEQUITYEquityIncentivePlansDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/COMMONSTOCKANDSTOCKHOLDERSEQUITYEquityIncentivePlansDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-aaa0-7046-88cd-bdcde149d70b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019c766a-aaa0-7311-8c85-fe074241da20" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-aaa0-7046-88cd-bdcde149d70b" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019c766a-aaa0-7311-8c85-fe074241da20" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_019c766a-aaa0-7326-906c-7e3ef1abaa0a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019c766a-aaa0-7311-8c85-fe074241da20" xlink:to="loc_us-gaap_AwardTypeAxis_019c766a-aaa0-7326-906c-7e3ef1abaa0a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-aaa0-7326-906c-7e3ef1abaa0a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_019c766a-aaa0-7326-906c-7e3ef1abaa0a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-aaa0-7326-906c-7e3ef1abaa0a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-aaa0-773e-974a-8ed094759fa0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_019c766a-aaa0-7326-906c-7e3ef1abaa0a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-aaa0-773e-974a-8ed094759fa0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_019c766a-aaa0-7e25-9212-ebcde95c90a3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-aaa0-773e-974a-8ed094759fa0" xlink:to="loc_us-gaap_EmployeeStockOptionMember_019c766a-aaa0-7e25-9212-ebcde95c90a3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_019c766a-aaa0-7cfa-842b-c5943aaeec54" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-aaa0-773e-974a-8ed094759fa0" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_019c766a-aaa0-7cfa-842b-c5943aaeec54" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VestingAxis_019c766a-aaa0-7a3d-9d6f-2da3c44e5d29" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VestingAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019c766a-aaa0-7311-8c85-fe074241da20" xlink:to="loc_us-gaap_VestingAxis_019c766a-aaa0-7a3d-9d6f-2da3c44e5d29" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VestingDomain_019c766a-aaa0-7a3d-9d6f-2da3c44e5d29_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VestingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VestingAxis_019c766a-aaa0-7a3d-9d6f-2da3c44e5d29" xlink:to="loc_us-gaap_VestingDomain_019c766a-aaa0-7a3d-9d6f-2da3c44e5d29_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VestingDomain_019c766a-aaa0-7197-99d5-223ccd36478e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VestingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VestingAxis_019c766a-aaa0-7a3d-9d6f-2da3c44e5d29" xlink:to="loc_us-gaap_VestingDomain_019c766a-aaa0-7197-99d5-223ccd36478e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationAwardTrancheOneMember_019c766a-aaa0-73bd-a597-4e4a1bbd3eea" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationAwardTrancheOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VestingDomain_019c766a-aaa0-7197-99d5-223ccd36478e" xlink:to="loc_us-gaap_ShareBasedCompensationAwardTrancheOneMember_019c766a-aaa0-73bd-a597-4e4a1bbd3eea" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019c766a-aaa0-7e83-a150-dc23aec345e1" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019c766a-aaa0-7311-8c85-fe074241da20" xlink:to="loc_srt_RangeAxis_019c766a-aaa0-7e83-a150-dc23aec345e1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019c766a-aaa0-7e83-a150-dc23aec345e1_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019c766a-aaa0-7e83-a150-dc23aec345e1" xlink:to="loc_srt_RangeMember_019c766a-aaa0-7e83-a150-dc23aec345e1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019c766a-aaa0-7c13-bd72-411e93f32777" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019c766a-aaa0-7e83-a150-dc23aec345e1" xlink:to="loc_srt_RangeMember_019c766a-aaa0-7c13-bd72-411e93f32777" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019c766a-aaa0-75ff-aead-c8a15f7ed406" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019c766a-aaa0-7c13-bd72-411e93f32777" xlink:to="loc_srt_MinimumMember_019c766a-aaa0-75ff-aead-c8a15f7ed406" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019c766a-aaa0-7c99-ac1a-f5a8fccabd8b" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019c766a-aaa0-7c13-bd72-411e93f32777" xlink:to="loc_srt_MaximumMember_019c766a-aaa0-7c99-ac1a-f5a8fccabd8b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_019c766a-aaa0-7b89-ba8e-84b588b4e3ba" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019c766a-aaa0-7311-8c85-fe074241da20" xlink:to="loc_us-gaap_PlanNameAxis_019c766a-aaa0-7b89-ba8e-84b588b4e3ba" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_019c766a-aaa0-7b89-ba8e-84b588b4e3ba_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_019c766a-aaa0-7b89-ba8e-84b588b4e3ba" xlink:to="loc_us-gaap_PlanNameDomain_019c766a-aaa0-7b89-ba8e-84b588b4e3ba_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_019c766a-aaa0-799e-ba1a-55c63300368c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_019c766a-aaa0-7b89-ba8e-84b588b4e3ba" xlink:to="loc_us-gaap_PlanNameDomain_019c766a-aaa0-799e-ba1a-55c63300368c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_EquityIncentivePlan20132020And2021Member_019c766a-aaa0-7e0e-881b-021294c5e593" xlink:href="hood-20251231.xsd#hood_EquityIncentivePlan20132020And2021Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_019c766a-aaa0-799e-ba1a-55c63300368c" xlink:to="loc_hood_EquityIncentivePlan20132020And2021Member_019c766a-aaa0-7e0e-881b-021294c5e593" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_EquityIncentivePlan2021Member_019c766a-aaa0-7e70-bfdf-07470729a8e0" xlink:href="hood-20251231.xsd#hood_EquityIncentivePlan2021Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_019c766a-aaa0-799e-ba1a-55c63300368c" xlink:to="loc_hood_EquityIncentivePlan2021Member_019c766a-aaa0-7e70-bfdf-07470729a8e0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_019c766a-aaa0-7e4c-b4dd-ff9a6e658f38" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019c766a-aaa0-7311-8c85-fe074241da20" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_019c766a-aaa0-7e4c-b4dd-ff9a6e658f38" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_019c766a-aaa0-7e4c-b4dd-ff9a6e658f38_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_019c766a-aaa0-7e4c-b4dd-ff9a6e658f38" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_019c766a-aaa0-7e4c-b4dd-ff9a6e658f38_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_019c766a-aaa0-7d01-9e34-113c16b0bc8c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_019c766a-aaa0-7e4c-b4dd-ff9a6e658f38" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_019c766a-aaa0-7d01-9e34-113c16b0bc8c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_019c766a-aaa0-795f-9c6a-4baf5f83d444" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_019c766a-aaa0-7d01-9e34-113c16b0bc8c" xlink:to="loc_us-gaap_SubsequentEventMember_019c766a-aaa0-795f-9c6a-4baf5f83d444" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_019c766a-aaa0-7cc5-b6a7-f71b6cc36f89" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-aaa0-7046-88cd-bdcde149d70b" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_019c766a-aaa0-7cc5-b6a7-f71b6cc36f89" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage_019c766a-aaa0-71e2-bbb6-52901c1d320b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-aaa0-7046-88cd-bdcde149d70b" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage_019c766a-aaa0-71e2-bbb6-52901c1d320b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_019c766a-aaa0-7cbb-8918-6b25bf5b32c2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-aaa0-7046-88cd-bdcde149d70b" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_019c766a-aaa0-7cbb-8918-6b25bf5b32c2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_019c766a-aaa0-726c-8aa1-4827c12cee3c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-aaa0-7046-88cd-bdcde149d70b" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_019c766a-aaa0-726c-8aa1-4827c12cee3c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod_019c766a-aaa0-738f-b692-cb768511815d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-aaa0-7046-88cd-bdcde149d70b" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod_019c766a-aaa0-738f-b692-cb768511815d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesReservedForIssuance_019c766a-aaa0-750e-945d-f25bcdb07f5e" xlink:href="hood-20251231.xsd#hood_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesReservedForIssuance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-aaa0-7046-88cd-bdcde149d70b" xlink:to="loc_hood_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesReservedForIssuance_019c766a-aaa0-750e-945d-f25bcdb07f5e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_019c766a-aaa0-7c58-8814-8f2c2c3fa367" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-aaa0-7046-88cd-bdcde149d70b" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_019c766a-aaa0-7c58-8814-8f2c2c3fa367" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/COMMONSTOCKANDSTOCKHOLDERSEQUITYScheduleOfActivityRelatedToTimeBasedDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#COMMONSTOCKANDSTOCKHOLDERSEQUITYScheduleOfActivityRelatedToTimeBasedDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/COMMONSTOCKANDSTOCKHOLDERSEQUITYScheduleOfActivityRelatedToTimeBasedDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-aaa0-7214-9bfe-0275f96619be" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019c766a-aaa0-7978-80c8-5c459e74a2af" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-aaa0-7214-9bfe-0275f96619be" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019c766a-aaa0-7978-80c8-5c459e74a2af" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_019c766a-aaa0-713c-953a-99ab2192d247" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019c766a-aaa0-7978-80c8-5c459e74a2af" xlink:to="loc_us-gaap_AwardTypeAxis_019c766a-aaa0-713c-953a-99ab2192d247" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-aaa0-713c-953a-99ab2192d247_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_019c766a-aaa0-713c-953a-99ab2192d247" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-aaa0-713c-953a-99ab2192d247_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-aaa0-752c-a865-86bff7f851d3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_019c766a-aaa0-713c-953a-99ab2192d247" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-aaa0-752c-a865-86bff7f851d3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_TimeBasedRestrictedStockUnitsRSUsMember_019c766a-aaa0-733d-b17a-bcaf872d0685" xlink:href="hood-20251231.xsd#hood_TimeBasedRestrictedStockUnitsRSUsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-aaa0-752c-a865-86bff7f851d3" xlink:to="loc_hood_TimeBasedRestrictedStockUnitsRSUsMember_019c766a-aaa0-733d-b17a-bcaf872d0685" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_019c766a-aaa0-7923-90f8-74a366435f03" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-aaa0-7214-9bfe-0275f96619be" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_019c766a-aaa0-7923-90f8-74a366435f03" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_019c766a-aaa0-7ed7-97c6-4017e92bac3c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_019c766a-aaa0-7923-90f8-74a366435f03" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_019c766a-aaa0-7ed7-97c6-4017e92bac3c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_019c766a-aaa0-7b9b-b9a9-cd9b6cbfb846" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_019c766a-aaa0-7923-90f8-74a366435f03" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_019c766a-aaa0-7b9b-b9a9-cd9b6cbfb846" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_019c766a-aaa0-7714-b990-efaa3a85b82a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_019c766a-aaa0-7923-90f8-74a366435f03" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_019c766a-aaa0-7714-b990-efaa3a85b82a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_019c766a-aaa0-7566-b1b0-c202ab753366" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_019c766a-aaa0-7923-90f8-74a366435f03" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_019c766a-aaa0-7566-b1b0-c202ab753366" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_019c766a-aaa0-7c9d-8ca5-94d137798d26" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_019c766a-aaa0-726c-96b5-ab5a38e73546" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-aaa0-7214-9bfe-0275f96619be" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_019c766a-aaa0-726c-96b5-ab5a38e73546" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_019c766a-aaa0-7183-84d1-403f3e2f8822" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_019c766a-aaa0-726c-96b5-ab5a38e73546" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_019c766a-aaa0-7183-84d1-403f3e2f8822" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_019c766a-aaa0-7030-9020-c14fa42bd45b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_019c766a-aaa0-726c-96b5-ab5a38e73546" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_019c766a-aaa0-7030-9020-c14fa42bd45b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_019c766a-aaa0-750b-802b-f948170b077d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_019c766a-aaa0-726c-96b5-ab5a38e73546" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_019c766a-aaa0-750b-802b-f948170b077d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_019c766a-aaa0-78e9-8e3b-c3894584f99f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_019c766a-aaa0-726c-96b5-ab5a38e73546" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_019c766a-aaa0-78e9-8e3b-c3894584f99f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_019c766a-aaa0-755f-839c-f2580095aef3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/COMMONSTOCKANDSTOCKHOLDERSEQUITYTimeBasedRSUsandMarketBasedRSUsDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#COMMONSTOCKANDSTOCKHOLDERSEQUITYTimeBasedRSUsandMarketBasedRSUsDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/COMMONSTOCKANDSTOCKHOLDERSEQUITYTimeBasedRSUsandMarketBasedRSUsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-ab4e-7b17-8121-9de5ed5f8a82" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019c766a-aaa0-740b-8285-395522644d2f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-ab4e-7b17-8121-9de5ed5f8a82" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019c766a-aaa0-740b-8285-395522644d2f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_019c766a-aaa0-794c-9207-0136c7b86e33" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019c766a-aaa0-740b-8285-395522644d2f" xlink:to="loc_us-gaap_AwardTypeAxis_019c766a-aaa0-794c-9207-0136c7b86e33" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-aaa0-794c-9207-0136c7b86e33_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_019c766a-aaa0-794c-9207-0136c7b86e33" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-aaa0-794c-9207-0136c7b86e33_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-aaa0-7486-8e1d-330e3156ce57" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_019c766a-aaa0-794c-9207-0136c7b86e33" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-aaa0-7486-8e1d-330e3156ce57" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_TimeBasedRestrictedStockUnitsRSUsMember_019c766a-aaa0-72ef-b362-e73c5cbdc220" xlink:href="hood-20251231.xsd#hood_TimeBasedRestrictedStockUnitsRSUsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-aaa0-7486-8e1d-330e3156ce57" xlink:to="loc_hood_TimeBasedRestrictedStockUnitsRSUsMember_019c766a-aaa0-72ef-b362-e73c5cbdc220" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_MarketBasedRestrictedStockUnitsRSUs2021Member_019c766a-aaa0-7a77-ba05-1bee2ce4f76f" xlink:href="hood-20251231.xsd#hood_MarketBasedRestrictedStockUnitsRSUs2021Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-aaa0-7486-8e1d-330e3156ce57" xlink:to="loc_hood_MarketBasedRestrictedStockUnitsRSUs2021Member_019c766a-aaa0-7a77-ba05-1bee2ce4f76f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_MarketBasedRestrictedStockUnitsRSUsMember_019c766a-aaa0-7ded-9a87-12c1caa2550c" xlink:href="hood-20251231.xsd#hood_MarketBasedRestrictedStockUnitsRSUsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-aaa0-7486-8e1d-330e3156ce57" xlink:to="loc_hood_MarketBasedRestrictedStockUnitsRSUsMember_019c766a-aaa0-7ded-9a87-12c1caa2550c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_019c766a-ab4e-7382-88e5-245ce362cbb2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019c766a-aaa0-740b-8285-395522644d2f" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_019c766a-ab4e-7382-88e5-245ce362cbb2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_019c766a-ab4e-7382-88e5-245ce362cbb2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_019c766a-ab4e-7382-88e5-245ce362cbb2" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_019c766a-ab4e-7382-88e5-245ce362cbb2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_019c766a-ab4e-7178-955a-9d7c6a68abf7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_019c766a-ab4e-7382-88e5-245ce362cbb2" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_019c766a-ab4e-7178-955a-9d7c6a68abf7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpenseMember_019c766a-ab4e-70a4-9647-45b28bb049c5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GeneralAndAdministrativeExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_019c766a-ab4e-7178-955a-9d7c6a68abf7" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpenseMember_019c766a-ab4e-70a4-9647-45b28bb049c5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_019c766a-ab4e-7f9f-a506-78b0c0101026" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-ab4e-7b17-8121-9de5ed5f8a82" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_019c766a-ab4e-7f9f-a506-78b0c0101026" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_019c766a-ab4e-793b-a252-b71d0acbba9b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-ab4e-7b17-8121-9de5ed5f8a82" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_019c766a-ab4e-793b-a252-b71d0acbba9b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_019c766a-ab4e-71c8-8e8f-41b61731c054" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-ab4e-7b17-8121-9de5ed5f8a82" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_019c766a-ab4e-71c8-8e8f-41b61731c054" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_019c766a-ab4e-7fd1-b42b-cdae38bc7317" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-ab4e-7b17-8121-9de5ed5f8a82" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_019c766a-ab4e-7fd1-b42b-cdae38bc7317" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/COMMONSTOCKANDSTOCKHOLDERSEQUITYEmployeeSharePurchasePlanDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#COMMONSTOCKANDSTOCKHOLDERSEQUITYEmployeeSharePurchasePlanDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/COMMONSTOCKANDSTOCKHOLDERSEQUITYEmployeeSharePurchasePlanDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-ab4e-7e7f-852a-1da729844b68" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019c766a-ab4e-7c0c-a3cd-fd69384bea1b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-ab4e-7e7f-852a-1da729844b68" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019c766a-ab4e-7c0c-a3cd-fd69384bea1b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_019c766a-ab4e-7d03-a47a-8c01d7c37fcb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019c766a-ab4e-7c0c-a3cd-fd69384bea1b" xlink:to="loc_us-gaap_AwardTypeAxis_019c766a-ab4e-7d03-a47a-8c01d7c37fcb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-ab4e-7d03-a47a-8c01d7c37fcb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_019c766a-ab4e-7d03-a47a-8c01d7c37fcb" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-ab4e-7d03-a47a-8c01d7c37fcb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-ab4e-7558-9e14-81e6cebbd171" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_019c766a-ab4e-7d03-a47a-8c01d7c37fcb" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-ab4e-7558-9e14-81e6cebbd171" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockMember_019c766a-ab4e-753e-94aa-37c0faab571f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-ab4e-7558-9e14-81e6cebbd171" xlink:to="loc_us-gaap_EmployeeStockMember_019c766a-ab4e-753e-94aa-37c0faab571f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_019c766a-ab4e-791b-93dc-ad568c89d802" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019c766a-ab4e-7c0c-a3cd-fd69384bea1b" xlink:to="loc_us-gaap_PlanNameAxis_019c766a-ab4e-791b-93dc-ad568c89d802" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_019c766a-ab4e-791b-93dc-ad568c89d802_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_019c766a-ab4e-791b-93dc-ad568c89d802" xlink:to="loc_us-gaap_PlanNameDomain_019c766a-ab4e-791b-93dc-ad568c89d802_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_019c766a-ab4e-7e70-842a-17e04233484a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_019c766a-ab4e-791b-93dc-ad568c89d802" xlink:to="loc_us-gaap_PlanNameDomain_019c766a-ab4e-7e70-842a-17e04233484a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_EmployeeSharePurchasePlan2021Member_019c766a-ab4e-791b-a0f0-2b8ebe4a4e96" xlink:href="hood-20251231.xsd#hood_EmployeeSharePurchasePlan2021Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_019c766a-ab4e-7e70-842a-17e04233484a" xlink:to="loc_hood_EmployeeSharePurchasePlan2021Member_019c766a-ab4e-791b-a0f0-2b8ebe4a4e96" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_019c766a-ab4e-7d3d-9489-ee283fec5061" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019c766a-ab4e-7c0c-a3cd-fd69384bea1b" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_019c766a-ab4e-7d3d-9489-ee283fec5061" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_019c766a-ab4e-7d3d-9489-ee283fec5061_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_019c766a-ab4e-7d3d-9489-ee283fec5061" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_019c766a-ab4e-7d3d-9489-ee283fec5061_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_019c766a-ab4e-7a1f-870e-0916273aec4d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_019c766a-ab4e-7d3d-9489-ee283fec5061" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_019c766a-ab4e-7a1f-870e-0916273aec4d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_019c766a-ab4e-744e-87fe-623ef825d5e4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_019c766a-ab4e-7a1f-870e-0916273aec4d" xlink:to="loc_us-gaap_SubsequentEventMember_019c766a-ab4e-744e-87fe-623ef825d5e4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSubscriptionRate_019c766a-ab4e-7d43-b609-22a6d2a59c83" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSubscriptionRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-ab4e-7e7f-852a-1da729844b68" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSubscriptionRate_019c766a-ab4e-7d43-b609-22a6d2a59c83" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPricePurchaseDate_019c766a-ab4e-7b1a-acc3-f8d6c2d86770" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPricePurchaseDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-ab4e-7e7f-852a-1da729844b68" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPricePurchaseDate_019c766a-ab4e-7b1a-acc3-f8d6c2d86770" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchaseProgramPeriodInForce1_019c766a-ab4e-7e32-90de-ea37a010096a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockRepurchaseProgramPeriodInForce1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-ab4e-7e7f-852a-1da729844b68" xlink:to="loc_us-gaap_StockRepurchaseProgramPeriodInForce1_019c766a-ab4e-7e32-90de-ea37a010096a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_ShareBasedCompensationArrangementByShareBasedPaymentAwardAnnualShareIncreaseAsAPercentageOfOutstandingShares_019c766a-ab4e-7fb6-808f-49331276583b" xlink:href="hood-20251231.xsd#hood_ShareBasedCompensationArrangementByShareBasedPaymentAwardAnnualShareIncreaseAsAPercentageOfOutstandingShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-ab4e-7e7f-852a-1da729844b68" xlink:to="loc_hood_ShareBasedCompensationArrangementByShareBasedPaymentAwardAnnualShareIncreaseAsAPercentageOfOutstandingShares_019c766a-ab4e-7fb6-808f-49331276583b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_019c766a-ab4e-7132-a0ea-d82975594c4c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-ab4e-7e7f-852a-1da729844b68" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_019c766a-ab4e-7132-a0ea-d82975594c4c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesPurchasedForAward_019c766a-ab4e-76b7-b3e2-8d63907f15a5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesPurchasedForAward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-ab4e-7e7f-852a-1da729844b68" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesPurchasedForAward_019c766a-ab4e-76b7-b3e2-8d63907f15a5" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPerShareWeightedAveragePriceOfSharesPurchased_019c766a-ab4e-7a86-9a32-fcfc4f9f462f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPerShareWeightedAveragePriceOfSharesPurchased"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-ab4e-7e7f-852a-1da729844b68" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPerShareWeightedAveragePriceOfSharesPurchased_019c766a-ab4e-7a86-9a32-fcfc4f9f462f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_019c766a-ab4e-74c8-acef-87f5cf6cb143" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-ab4e-7e7f-852a-1da729844b68" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_019c766a-ab4e-74c8-acef-87f5cf6cb143" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized_019c766a-ab4e-770b-9c54-08a36dc22b23" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-ab4e-7e7f-852a-1da729844b68" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized_019c766a-ab4e-770b-9c54-08a36dc22b23" xlink:type="arc" order="8"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/COMMONSTOCKANDSTOCKHOLDERSEQUITYAcquisitionofTradePMRDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#COMMONSTOCKANDSTOCKHOLDERSEQUITYAcquisitionofTradePMRDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/COMMONSTOCKANDSTOCKHOLDERSEQUITYAcquisitionofTradePMRDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-ab4e-7159-b9f0-45d02cdafd04" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019c766a-ab4e-791f-a23c-3d58e92f646b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-ab4e-7159-b9f0-45d02cdafd04" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019c766a-ab4e-791f-a23c-3d58e92f646b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_019c766a-ab4e-7c51-a46f-49da90b4dc1d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019c766a-ab4e-791f-a23c-3d58e92f646b" xlink:to="loc_us-gaap_AwardTypeAxis_019c766a-ab4e-7c51-a46f-49da90b4dc1d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-ab4e-7c51-a46f-49da90b4dc1d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_019c766a-ab4e-7c51-a46f-49da90b4dc1d" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-ab4e-7c51-a46f-49da90b4dc1d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-ab4e-765a-9439-ac29758c9769" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_019c766a-ab4e-7c51-a46f-49da90b4dc1d" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-ab4e-765a-9439-ac29758c9769" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_TradePMRRestrictedStockUnitsRSUsMember_019c766a-ab4e-77d5-a340-df248a4456ec" xlink:href="hood-20251231.xsd#hood_TradePMRRestrictedStockUnitsRSUsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-ab4e-765a-9439-ac29758c9769" xlink:to="loc_hood_TradePMRRestrictedStockUnitsRSUsMember_019c766a-ab4e-77d5-a340-df248a4456ec" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_019c766a-ab4e-7b77-82a5-bc43daf82d7f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019c766a-ab4e-791f-a23c-3d58e92f646b" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_019c766a-ab4e-7b77-82a5-bc43daf82d7f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-ab4e-7b77-82a5-bc43daf82d7f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019c766a-ab4e-7b77-82a5-bc43daf82d7f" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-ab4e-7b77-82a5-bc43daf82d7f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-ab4e-749b-930e-131372c7ea3a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_019c766a-ab4e-7b77-82a5-bc43daf82d7f" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-ab4e-749b-930e-131372c7ea3a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_TradePMRMember_019c766a-ab4e-7c83-ad6f-568efd1a99e2" xlink:href="hood-20251231.xsd#hood_TradePMRMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_019c766a-ab4e-749b-930e-131372c7ea3a" xlink:to="loc_hood_TradePMRMember_019c766a-ab4e-7c83-ad6f-568efd1a99e2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019c766a-ab4e-711b-be5c-8ab91591d9f9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_019c766a-ab4e-791f-a23c-3d58e92f646b" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019c766a-ab4e-711b-be5c-8ab91591d9f9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019c766a-ab4e-711b-be5c-8ab91591d9f9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019c766a-ab4e-711b-be5c-8ab91591d9f9" xlink:to="loc_us-gaap_ClassOfStockDomain_019c766a-ab4e-711b-be5c-8ab91591d9f9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019c766a-ab4e-7cf5-b752-77b91bb018e4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019c766a-ab4e-711b-be5c-8ab91591d9f9" xlink:to="loc_us-gaap_ClassOfStockDomain_019c766a-ab4e-7cf5-b752-77b91bb018e4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_019c766a-ab4e-73cf-902c-6a4f315fb59e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonClassAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019c766a-ab4e-7cf5-b752-77b91bb018e4" xlink:to="loc_us-gaap_CommonClassAMember_019c766a-ab4e-73cf-902c-6a4f315fb59e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_019c766a-ab4e-77bf-9428-6f2dc19035e2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-ab4e-7159-b9f0-45d02cdafd04" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_019c766a-ab4e-77bf-9428-6f2dc19035e2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable_019c766a-ab4e-77c6-a2ff-29a3a75dd130" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-ab4e-7159-b9f0-45d02cdafd04" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable_019c766a-ab4e-77c6-a2ff-29a3a75dd130" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_019c766a-ab4e-7f5f-9e45-b95e7a14414d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-ab4e-7159-b9f0-45d02cdafd04" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_019c766a-ab4e-7f5f-9e45-b95e7a14414d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_019c766a-ab4e-7a4c-9122-7aa71cc21d46" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-ab4e-7159-b9f0-45d02cdafd04" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_019c766a-ab4e-7a4c-9122-7aa71cc21d46" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_019c766a-ab4e-74f1-aee5-db3e2f04c034" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_019c766a-ab4e-7a4c-9122-7aa71cc21d46" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_019c766a-ab4e-74f1-aee5-db3e2f04c034" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_019c766a-ab4e-7058-ab45-3e5a7cd5383f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_019c766a-ab4e-733a-9698-f17f3971e94d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_019c766a-ab4e-7a4c-9122-7aa71cc21d46" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_019c766a-ab4e-733a-9698-f17f3971e94d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_019c766a-ab4e-7a79-946f-0e324939aee8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_019c766a-ab4e-7a4c-9122-7aa71cc21d46" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_019c766a-ab4e-7a79-946f-0e324939aee8" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_019c766a-ab4e-7900-a888-1e0287b76b88" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_019c766a-ab4e-7533-8d51-32cac0d77b0a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_019c766a-ab4e-7159-b9f0-45d02cdafd04" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_019c766a-ab4e-7533-8d51-32cac0d77b0a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_019c766a-ab4e-75fc-8497-d74e194b8788" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_019c766a-ab4e-7533-8d51-32cac0d77b0a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_019c766a-ab4e-75fc-8497-d74e194b8788" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_019c766a-ab4e-7b3c-9845-bd4b50d0d7f0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_019c766a-ab4e-7533-8d51-32cac0d77b0a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_019c766a-ab4e-7b3c-9845-bd4b50d0d7f0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_019c766a-ab4e-779b-95ec-25f9cbc3ebf1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_019c766a-ab4e-7533-8d51-32cac0d77b0a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_019c766a-ab4e-779b-95ec-25f9cbc3ebf1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_019c766a-ab4e-7f43-82b1-a01b35b6cb76" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_019c766a-ab4e-7533-8d51-32cac0d77b0a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_019c766a-ab4e-7f43-82b1-a01b35b6cb76" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_019c766a-ab4e-76e6-a9b6-d7a6fb6551df" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/COMMONSTOCKANDSTOCKHOLDERSEQUITYScheduleOfShareBasedCompensationDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#COMMONSTOCKANDSTOCKHOLDERSEQUITYScheduleOfShareBasedCompensationDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/COMMONSTOCKANDSTOCKHOLDERSEQUITYScheduleOfShareBasedCompensationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_019c766a-ab4e-7d6a-93a5-d929e064922a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_019c766a-ab4e-7051-80ad-462296c9e489" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_019c766a-ab4e-7d6a-93a5-d929e064922a" xlink:to="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_019c766a-ab4e-7051-80ad-462296c9e489" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_019c766a-ab4e-7128-963f-0230817dff48" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_019c766a-ab4e-7051-80ad-462296c9e489" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_019c766a-ab4e-7128-963f-0230817dff48" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_019c766a-ab4e-7128-963f-0230817dff48_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_019c766a-ab4e-7128-963f-0230817dff48" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_019c766a-ab4e-7128-963f-0230817dff48_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_019c766a-ab4e-7b08-9137-da937b72611f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_019c766a-ab4e-7128-963f-0230817dff48" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_019c766a-ab4e-7b08-9137-da937b72611f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_BrokerageAndTransactionExpenseMember_019c766a-ab4e-7f5a-b5a1-83a7e9265b0a" xlink:href="hood-20251231.xsd#hood_BrokerageAndTransactionExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_019c766a-ab4e-7b08-9137-da937b72611f" xlink:to="loc_hood_BrokerageAndTransactionExpenseMember_019c766a-ab4e-7f5a-b5a1-83a7e9265b0a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_TechnologyAndDevelopmentExpenseMember_019c766a-ab4e-7df1-85bf-7d69ef7d7f29" xlink:href="hood-20251231.xsd#hood_TechnologyAndDevelopmentExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_019c766a-ab4e-7b08-9137-da937b72611f" xlink:to="loc_hood_TechnologyAndDevelopmentExpenseMember_019c766a-ab4e-7df1-85bf-7d69ef7d7f29" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpenseMember_019c766a-ab4e-7859-ba4f-ca5babc85fa8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_019c766a-ab4e-7b08-9137-da937b72611f" xlink:to="loc_us-gaap_OperatingExpenseMember_019c766a-ab4e-7859-ba4f-ca5babc85fa8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingAndMarketingExpenseMember_019c766a-ab4e-76bb-90a7-ae2ddc84a067" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SellingAndMarketingExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_019c766a-ab4e-7b08-9137-da937b72611f" xlink:to="loc_us-gaap_SellingAndMarketingExpenseMember_019c766a-ab4e-76bb-90a7-ae2ddc84a067" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpenseMember_019c766a-ab4e-7f64-a225-7bdedc068a97" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GeneralAndAdministrativeExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_019c766a-ab4e-7b08-9137-da937b72611f" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpenseMember_019c766a-ab4e-7f64-a225-7bdedc068a97" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_019c766a-ab4e-788e-98b0-2598b545f014" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_019c766a-ab4e-7051-80ad-462296c9e489" xlink:to="loc_us-gaap_AwardTypeAxis_019c766a-ab4e-788e-98b0-2598b545f014" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-ab4e-788e-98b0-2598b545f014_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_019c766a-ab4e-788e-98b0-2598b545f014" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-ab4e-788e-98b0-2598b545f014_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-ab4e-7ddb-b83a-f767b5894133" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_019c766a-ab4e-788e-98b0-2598b545f014" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-ab4e-7ddb-b83a-f767b5894133" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_TimeBasedRestrictedStockUnitsRSUsMember_019c766a-ab4e-74e6-a2dd-7b50b03fcc9b" xlink:href="hood-20251231.xsd#hood_TimeBasedRestrictedStockUnitsRSUsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-ab4e-7ddb-b83a-f767b5894133" xlink:to="loc_hood_TimeBasedRestrictedStockUnitsRSUsMember_019c766a-ab4e-74e6-a2dd-7b50b03fcc9b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_MarketBasedRestrictedStockUnitsRSUsMember_019c766a-ab4e-75ab-9965-e8624dd06208" xlink:href="hood-20251231.xsd#hood_MarketBasedRestrictedStockUnitsRSUsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_019c766a-ab4e-7ddb-b83a-f767b5894133" xlink:to="loc_hood_MarketBasedRestrictedStockUnitsRSUsMember_019c766a-ab4e-75ab-9965-e8624dd06208" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_019c766a-ab4e-762d-8c2f-5b8e213b0584" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_019c766a-ab4e-7d6a-93a5-d929e064922a" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_019c766a-ab4e-762d-8c2f-5b8e213b0584" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_ShareBasedPaymentArrangementExpenseReversal_019c766a-ab4e-7f17-b50a-57d2d72c1560" xlink:href="hood-20251231.xsd#hood_ShareBasedPaymentArrangementExpenseReversal"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_019c766a-ab4e-7d6a-93a5-d929e064922a" xlink:to="loc_hood_ShareBasedPaymentArrangementExpenseReversal_019c766a-ab4e-7f17-b50a-57d2d72c1560" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/NETINCOMELOSSPERSHAREScheduleofBasicandDilutedLossPerShareDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#NETINCOMELOSSPERSHAREScheduleofBasicandDilutedLossPerShareDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/NETINCOMELOSSPERSHAREScheduleofBasicandDilutedLossPerShareDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockLineItems_019c766a-ab4e-78ee-93a9-1fb6f786cf68" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_019c766a-ab4e-7df2-866a-9745b5643bf2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfStockByClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_019c766a-ab4e-78ee-93a9-1fb6f786cf68" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_019c766a-ab4e-7df2-866a-9745b5643bf2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019c766a-ab4e-73d7-984d-d1d385c9452f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_019c766a-ab4e-7df2-866a-9745b5643bf2" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019c766a-ab4e-73d7-984d-d1d385c9452f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019c766a-ab4e-73d7-984d-d1d385c9452f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019c766a-ab4e-73d7-984d-d1d385c9452f" xlink:to="loc_us-gaap_ClassOfStockDomain_019c766a-ab4e-73d7-984d-d1d385c9452f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019c766a-ab4e-7fd9-bdb2-c2cfed757ace" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019c766a-ab4e-73d7-984d-d1d385c9452f" xlink:to="loc_us-gaap_ClassOfStockDomain_019c766a-ab4e-7fd9-bdb2-c2cfed757ace" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_019c766a-ab4e-796f-960f-264d0f24ba02" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonClassAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019c766a-ab4e-7fd9-bdb2-c2cfed757ace" xlink:to="loc_us-gaap_CommonClassAMember_019c766a-ab4e-796f-960f-264d0f24ba02" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassBMember_019c766a-ab4e-7114-9050-ec776f543559" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonClassBMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019c766a-ab4e-7fd9-bdb2-c2cfed757ace" xlink:to="loc_us-gaap_CommonClassBMember_019c766a-ab4e-7114-9050-ec776f543559" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasicAbstract_019c766a-ab4e-7b98-9ce0-5997a3dcb4c9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EarningsPerShareBasicAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019c766a-ab4e-78ee-93a9-1fb6f786cf68" xlink:to="loc_us-gaap_EarningsPerShareBasicAbstract_019c766a-ab4e-7b98-9ce0-5997a3dcb4c9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasicAbstract_019c766a-ab4e-7918-a217-f20628341328" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasicAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicAbstract_019c766a-ab4e-7b98-9ce0-5997a3dcb4c9" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasicAbstract_019c766a-ab4e-7918-a217-f20628341328" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019c766a-ab4e-7d38-84d8-c916e7527251" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasicAbstract_019c766a-ab4e-7918-a217-f20628341328" xlink:to="loc_us-gaap_NetIncomeLoss_019c766a-ab4e-7d38-84d8-c916e7527251" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAttributableToRedeemableNoncontrollingInterest_019c766a-ab4e-71c3-a5ac-501a294ecfcc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLossAttributableToRedeemableNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasicAbstract_019c766a-ab4e-7918-a217-f20628341328" xlink:to="loc_us-gaap_NetIncomeLossAttributableToRedeemableNoncontrollingInterest_019c766a-ab4e-71c3-a5ac-501a294ecfcc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019c766a-ab4e-764b-97ef-d1c31b8749ac" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasicAbstract_019c766a-ab4e-7918-a217-f20628341328" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019c766a-ab4e-764b-97ef-d1c31b8749ac" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasicAbstract_019c766a-ab4e-78b0-bb71-4cb8e09e3460" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasicAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicAbstract_019c766a-ab4e-7b98-9ce0-5997a3dcb4c9" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasicAbstract_019c766a-ab4e-78b0-bb71-4cb8e09e3460" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019c766a-ab4e-7538-a409-d2835895a706" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasicAbstract_019c766a-ab4e-78b0-bb71-4cb8e09e3460" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019c766a-ab4e-7538-a409-d2835895a706" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_019c766a-ab4e-78a5-8a89-2308815c4887" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicAbstract_019c766a-ab4e-7b98-9ce0-5997a3dcb4c9" xlink:to="loc_us-gaap_EarningsPerShareBasic_019c766a-ab4e-78a5-8a89-2308815c4887" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDilutedAbstract_019c766a-ab4e-7475-bc2b-69e84ba8d8a0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EarningsPerShareDilutedAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019c766a-ab4e-78ee-93a9-1fb6f786cf68" xlink:to="loc_us-gaap_EarningsPerShareDilutedAbstract_019c766a-ab4e-7475-bc2b-69e84ba8d8a0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAttributableToParentDilutedAbstract_019c766a-ab4e-7908-a3b7-b0797c6ac423" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLossAttributableToParentDilutedAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareDilutedAbstract_019c766a-ab4e-7475-bc2b-69e84ba8d8a0" xlink:to="loc_us-gaap_NetIncomeLossAttributableToParentDilutedAbstract_019c766a-ab4e-7908-a3b7-b0797c6ac423" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019c766a-ab4e-798d-bfa0-ffa14210a3b6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLoss"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAttributableToRedeemableNoncontrollingInterest_019c766a-ab4e-7141-b0de-a27d8eeae00c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLossAttributableToRedeemableNoncontrollingInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019c766a-ab4e-700a-92d0-c1124cde22e4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DilutiveSecuritiesEffectOnBasicEarningsPerShareOther_019c766a-ab4e-7868-a2c6-1a5d22f03bf0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DilutiveSecuritiesEffectOnBasicEarningsPerShareOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetIncomeLossAttributableToParentDilutedAbstract_019c766a-ab4e-7908-a3b7-b0797c6ac423" xlink:to="loc_us-gaap_DilutiveSecuritiesEffectOnBasicEarningsPerShareOther_019c766a-ab4e-7868-a2c6-1a5d22f03bf0" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_DilutiveSecuritiesEffectOnBasicEarningsDilutiveEffectOfReallocationOfNetIncomeToCommonStock_019c766a-ab4e-728b-a884-9d89418787eb" xlink:href="hood-20251231.xsd#hood_DilutiveSecuritiesEffectOnBasicEarningsDilutiveEffectOfReallocationOfNetIncomeToCommonStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetIncomeLossAttributableToParentDilutedAbstract_019c766a-ab4e-7908-a3b7-b0797c6ac423" xlink:to="loc_hood_DilutiveSecuritiesEffectOnBasicEarningsDilutiveEffectOfReallocationOfNetIncomeToCommonStock_019c766a-ab4e-728b-a884-9d89418787eb" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted_019c766a-ab4e-7234-aa6c-eb8fb0376176" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetIncomeLossAttributableToParentDilutedAbstract_019c766a-ab4e-7908-a3b7-b0797c6ac423" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted_019c766a-ab4e-7234-aa6c-eb8fb0376176" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_019c766a-ab4e-7ad4-939a-3d29b0918be8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareDilutedAbstract_019c766a-ab4e-7475-bc2b-69e84ba8d8a0" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_019c766a-ab4e-7ad4-939a-3d29b0918be8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_019c766a-ab4e-73ca-8878-51fe84cd19a6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_IncrementalCommonSharesAttributableToDilutiveEffectOfShareBasedPaymentArrangementsAndWarrants_019c766a-ab4e-7db8-9a44-6abb80655bea" xlink:href="hood-20251231.xsd#hood_IncrementalCommonSharesAttributableToDilutiveEffectOfShareBasedPaymentArrangementsAndWarrants"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_019c766a-ab4e-7ad4-939a-3d29b0918be8" xlink:to="loc_hood_IncrementalCommonSharesAttributableToDilutiveEffectOfShareBasedPaymentArrangementsAndWarrants_019c766a-ab4e-7db8-9a44-6abb80655bea" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_IncrementalCommonSharesAttributableToDilutiveEffectOfConversionOfCommonStock_019c766a-ab4e-7958-9cbc-e50064e624a8" xlink:href="hood-20251231.xsd#hood_IncrementalCommonSharesAttributableToDilutiveEffectOfConversionOfCommonStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_019c766a-ab4e-7ad4-939a-3d29b0918be8" xlink:to="loc_hood_IncrementalCommonSharesAttributableToDilutiveEffectOfConversionOfCommonStock_019c766a-ab4e-7958-9cbc-e50064e624a8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019c766a-ab4e-72d5-ad73-7f1d311b7c32" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_019c766a-ab4e-7ad4-939a-3d29b0918be8" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_019c766a-ab4e-72d5-ad73-7f1d311b7c32" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_019c766a-ab4e-73df-984a-02e8bcbd1635" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareDilutedAbstract_019c766a-ab4e-7475-bc2b-69e84ba8d8a0" xlink:to="loc_us-gaap_EarningsPerShareDiluted_019c766a-ab4e-73df-984a-02e8bcbd1635" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/NETINCOMELOSSPERSHAREScheduleofPotentialCommonSharesExcludedfromtheCalculationofDilutedNetIncomeLossPerShareDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#NETINCOMELOSSPERSHAREScheduleofPotentialCommonSharesExcludedfromtheCalculationofDilutedNetIncomeLossPerShareDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/NETINCOMELOSSPERSHAREScheduleofPotentialCommonSharesExcludedfromtheCalculationofDilutedNetIncomeLossPerShareDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_019c766a-ab4e-7c22-9523-5cb2c98cbad5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_019c766a-ab4e-7a57-83d5-0a1a82bb00fe" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_019c766a-ab4e-7c22-9523-5cb2c98cbad5" xlink:to="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_019c766a-ab4e-7a57-83d5-0a1a82bb00fe" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_019c766a-ab4e-77e9-80ad-54797a4ec6ed" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_019c766a-ab4e-7a57-83d5-0a1a82bb00fe" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_019c766a-ab4e-77e9-80ad-54797a4ec6ed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_019c766a-ab4e-77e9-80ad-54797a4ec6ed_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_019c766a-ab4e-77e9-80ad-54797a4ec6ed" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_019c766a-ab4e-77e9-80ad-54797a4ec6ed_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_019c766a-ab4e-7bdc-8fe1-fcaaddfcd13b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_019c766a-ab4e-77e9-80ad-54797a4ec6ed" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_019c766a-ab4e-7bdc-8fe1-fcaaddfcd13b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_TimeBasedRestrictedStockUnitsRSUsMember_019c766a-ab4e-76f4-9713-ed6d7e950db6" xlink:href="hood-20251231.xsd#hood_TimeBasedRestrictedStockUnitsRSUsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_019c766a-ab4e-7bdc-8fe1-fcaaddfcd13b" xlink:to="loc_hood_TimeBasedRestrictedStockUnitsRSUsMember_019c766a-ab4e-76f4-9713-ed6d7e950db6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_MarketBasedRestrictedStockUnitsRSUsMember_019c766a-ab4e-75c2-a349-8a11d8eeca50" xlink:href="hood-20251231.xsd#hood_MarketBasedRestrictedStockUnitsRSUsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_019c766a-ab4e-7bdc-8fe1-fcaaddfcd13b" xlink:to="loc_hood_MarketBasedRestrictedStockUnitsRSUsMember_019c766a-ab4e-75c2-a349-8a11d8eeca50" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_019c766a-ab4e-7146-a1e3-c24cdacee57b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_019c766a-ab4e-7bdc-8fe1-fcaaddfcd13b" xlink:to="loc_us-gaap_EmployeeStockOptionMember_019c766a-ab4e-7146-a1e3-c24cdacee57b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WarrantMember_019c766a-ab4e-767e-be79-8a61b4913fb7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_WarrantMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_019c766a-ab4e-7bdc-8fe1-fcaaddfcd13b" xlink:to="loc_us-gaap_WarrantMember_019c766a-ab4e-767e-be79-8a61b4913fb7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockMember_019c766a-ab4e-740d-b067-592c9f43eaf2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_019c766a-ab4e-7bdc-8fe1-fcaaddfcd13b" xlink:to="loc_us-gaap_EmployeeStockMember_019c766a-ab4e-740d-b067-592c9f43eaf2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_019c766a-ab4e-7f57-87a5-b14c8d65b933" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_019c766a-ab4e-7c22-9523-5cb2c98cbad5" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_019c766a-ab4e-7f57-87a5-b14c8d65b933" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/LEASESNarrativeDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#LEASESNarrativeDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/LEASESNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionLineItems_019c766a-ab4e-71e1-ae7f-f4b5df23e2f0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeLeaseDescriptionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionTable_019c766a-ab4e-7340-b92d-7480e0ebbe4c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeLeaseDescriptionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_019c766a-ab4e-71e1-ae7f-f4b5df23e2f0" xlink:to="loc_us-gaap_LesseeLeaseDescriptionTable_019c766a-ab4e-7340-b92d-7480e0ebbe4c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019c766a-ab4e-7539-bf4e-11b3182f83ff" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_019c766a-ab4e-7340-b92d-7480e0ebbe4c" xlink:to="loc_srt_RangeAxis_019c766a-ab4e-7539-bf4e-11b3182f83ff" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019c766a-ab4e-7539-bf4e-11b3182f83ff_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019c766a-ab4e-7539-bf4e-11b3182f83ff" xlink:to="loc_srt_RangeMember_019c766a-ab4e-7539-bf4e-11b3182f83ff_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019c766a-ab4e-7c80-90fa-273c1dc644bc" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019c766a-ab4e-7539-bf4e-11b3182f83ff" xlink:to="loc_srt_RangeMember_019c766a-ab4e-7c80-90fa-273c1dc644bc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019c766a-ab4e-7b06-bd88-8eafa6a904e4" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019c766a-ab4e-7c80-90fa-273c1dc644bc" xlink:to="loc_srt_MinimumMember_019c766a-ab4e-7b06-bd88-8eafa6a904e4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019c766a-ab4e-7a18-9bbd-46e94232c1c4" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019c766a-ab4e-7c80-90fa-273c1dc644bc" xlink:to="loc_srt_MaximumMember_019c766a-ab4e-7a18-9bbd-46e94232c1c4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseRemainingLeaseTerm_019c766a-ab4e-73f6-9003-9d29d72c4671" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseRemainingLeaseTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_019c766a-ab4e-71e1-ae7f-f4b5df23e2f0" xlink:to="loc_us-gaap_LesseeOperatingLeaseRemainingLeaseTerm_019c766a-ab4e-73f6-9003-9d29d72c4671" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_LesseeOperatingLeaseNumberOfRenewalOptions_019c766a-ab4e-7ac4-b369-abbfc883fd9e" xlink:href="hood-20251231.xsd#hood_LesseeOperatingLeaseNumberOfRenewalOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_019c766a-ab4e-71e1-ae7f-f4b5df23e2f0" xlink:to="loc_hood_LesseeOperatingLeaseNumberOfRenewalOptions_019c766a-ab4e-7ac4-b369-abbfc883fd9e" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://robinhood.com/role/COMMITMENTSCONTINGENCIESDetails" xlink:type="simple" xlink:href="hood-20251231.xsd#COMMITMENTSCONTINGENCIESDetails"/>
  <link:definitionLink xlink:role="http://robinhood.com/role/COMMITMENTSCONTINGENCIESDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesLineItems_019c766a-ab4e-7924-bb99-dba590558e2c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LossContingenciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesTable_019c766a-ab4e-7205-a6b8-c71e71b69945" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LossContingenciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LossContingenciesLineItems_019c766a-ab4e-7924-bb99-dba590558e2c" xlink:to="loc_us-gaap_LossContingenciesTable_019c766a-ab4e-7205-a6b8-c71e71b69945" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseAxis_019c766a-ab4e-7da8-a1fc-1cea1dc1823f" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_LitigationCaseAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_019c766a-ab4e-7205-a6b8-c71e71b69945" xlink:to="loc_srt_LitigationCaseAxis_019c766a-ab4e-7da8-a1fc-1cea1dc1823f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_019c766a-ab4e-7da8-a1fc-1cea1dc1823f_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_LitigationCaseTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_LitigationCaseAxis_019c766a-ab4e-7da8-a1fc-1cea1dc1823f" xlink:to="loc_srt_LitigationCaseTypeDomain_019c766a-ab4e-7da8-a1fc-1cea1dc1823f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_019c766a-ab4e-7a5f-b51c-8a248fe822c4" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_LitigationCaseTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_LitigationCaseAxis_019c766a-ab4e-7da8-a1fc-1cea1dc1823f" xlink:to="loc_srt_LitigationCaseTypeDomain_019c766a-ab4e-7a5f-b51c-8a248fe822c4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_PutativeSecuritiesFraudClassActionLawsuitMember_019c766a-ab4e-7356-9aee-0dfbf92732d3" xlink:href="hood-20251231.xsd#hood_PutativeSecuritiesFraudClassActionLawsuitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_LitigationCaseTypeDomain_019c766a-ab4e-7a5f-b51c-8a248fe822c4" xlink:to="loc_hood_PutativeSecuritiesFraudClassActionLawsuitMember_019c766a-ab4e-7356-9aee-0dfbf92732d3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyAccrualAtCarryingValue_019c766a-ab4e-7010-a452-39ab426e84d1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LossContingencyAccrualAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019c766a-ab4e-7924-bb99-dba590558e2c" xlink:to="loc_us-gaap_LossContingencyAccrualAtCarryingValue_019c766a-ab4e-7010-a452-39ab426e84d1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNewClaimsFiledNumber_019c766a-ab4e-7c70-90fb-e9a5ea2131cd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LossContingencyNewClaimsFiledNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019c766a-ab4e-7924-bb99-dba590558e2c" xlink:to="loc_us-gaap_LossContingencyNewClaimsFiledNumber_019c766a-ab4e-7c70-90fb-e9a5ea2131cd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_LossContingencyPlaintiffClaimsNumberOfTranches_019c766a-ab4e-7c19-9c9b-dcd9584c6213" xlink:href="hood-20251231.xsd#hood_LossContingencyPlaintiffClaimsNumberOfTranches"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019c766a-ab4e-7924-bb99-dba590558e2c" xlink:to="loc_hood_LossContingencyPlaintiffClaimsNumberOfTranches_019c766a-ab4e-7c19-9c9b-dcd9584c6213" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingencies_019c766a-ab4e-740c-ae22-cfe3564e2c34" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommitmentsAndContingencies"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019c766a-ab4e-7924-bb99-dba590558e2c" xlink:to="loc_us-gaap_CommitmentsAndContingencies_019c766a-ab4e-740c-ae22-cfe3564e2c34" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyPendingClaimsNumber_019c766a-ab4e-73fa-9c22-109bc13491ea" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LossContingencyPendingClaimsNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_019c766a-ab4e-7924-bb99-dba590558e2c" xlink:to="loc_us-gaap_LossContingencyPendingClaimsNumber_019c766a-ab4e-73fa-9c22-109bc13491ea" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="simple" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-roles-2025.xsd#eedm"/>
  <link:definitionLink xlink:role="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherAssetsNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract" xlink:to="loc_us-gaap_OtherAssetsNoncurrent" xlink:type="arc" order="101"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://xbrl.sec.gov/ecd/role/IndividualsOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#IndividualsOnly"/>
  <link:definitionLink xlink:role="http://xbrl.sec.gov/ecd/role/IndividualsOnly" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AllIndividualsMember" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_AllIndividualsMember"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_BaijuPrafulkumarBhattLivingTrustMember_019c766a-a786-7d98-9e4b-6d10329b670f" xlink:href="hood-20251231.xsd#hood_BaijuPrafulkumarBhattLivingTrustMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_hood_BaijuPrafulkumarBhattLivingTrustMember_019c766a-a786-7d98-9e4b-6d10329b670f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_StevenQuirkMember_019c766a-a786-78e0-b6b0-500f814a106f" xlink:href="hood-20251231.xsd#hood_StevenQuirkMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_hood_StevenQuirkMember_019c766a-a786-78e0-b6b0-500f814a106f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_JonathanJ.RubinsteinTrustMember_019c766a-a786-7836-8497-4a7398aa810b" xlink:href="hood-20251231.xsd#hood_JonathanJ.RubinsteinTrustMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_hood_JonathanJ.RubinsteinTrustMember_019c766a-a786-7836-8497-4a7398aa810b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_PaulaLoopMember_019c766a-a786-7014-8b8a-d3bc98f58097" xlink:href="hood-20251231.xsd#hood_PaulaLoopMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_hood_PaulaLoopMember_019c766a-a786-7014-8b8a-d3bc98f58097" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_DaraTresederMember_019c766a-a786-72d1-86ed-9440fe33cb7c" xlink:href="hood-20251231.xsd#hood_DaraTresederMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_hood_DaraTresederMember_019c766a-a786-72d1-86ed-9440fe33cb7c" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://xbrl.sec.gov/ecd/role/TradingArrangementsOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#TradingArrangmentsOnly"/>
  <link:definitionLink xlink:role="http://xbrl.sec.gov/ecd/role/TradingArrangementsOnly" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AllTradingArrangementsMember" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_AllTradingArrangementsMember"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_StevenQuirkRuleTradingArrangementClassACommonStockLessSharesPreviouslySoldUnderPredecessorRule10b51TradingArrangementsMember_019c766a-a786-7567-9328-25665c6bbcba" xlink:href="hood-20251231.xsd#hood_StevenQuirkRuleTradingArrangementClassACommonStockLessSharesPreviouslySoldUnderPredecessorRule10b51TradingArrangementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllTradingArrangementsMember" xlink:to="loc_hood_StevenQuirkRuleTradingArrangementClassACommonStockLessSharesPreviouslySoldUnderPredecessorRule10b51TradingArrangementsMember_019c766a-a786-7567-9328-25665c6bbcba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_StevenQuirkRuleTradingArrangementUnvestedRSUsLessSharesPreviouslySoldUnderPredecessorRule10b51TradingArrangementsMember_019c766a-a786-7868-b0be-a54186673c43" xlink:href="hood-20251231.xsd#hood_StevenQuirkRuleTradingArrangementUnvestedRSUsLessSharesPreviouslySoldUnderPredecessorRule10b51TradingArrangementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllTradingArrangementsMember" xlink:to="loc_hood_StevenQuirkRuleTradingArrangementUnvestedRSUsLessSharesPreviouslySoldUnderPredecessorRule10b51TradingArrangementsMember_019c766a-a786-7868-b0be-a54186673c43" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_StevenQuirkRuleTradingArrangementClassACommonStockMember_019c766a-a786-7eec-abbf-24c8c65f1e01" xlink:href="hood-20251231.xsd#hood_StevenQuirkRuleTradingArrangementClassACommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllTradingArrangementsMember" xlink:to="loc_hood_StevenQuirkRuleTradingArrangementClassACommonStockMember_019c766a-a786-7eec-abbf-24c8c65f1e01" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_hood_StevenQuirkRuleTradingArrangementUnvestedRSUsLessSharesWithheldForApplicableTaxesMember_019c766a-a786-7617-b37f-4179cd03ed4f" xlink:href="hood-20251231.xsd#hood_StevenQuirkRuleTradingArrangementUnvestedRSUsLessSharesWithheldForApplicableTaxesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllTradingArrangementsMember" xlink:to="loc_hood_StevenQuirkRuleTradingArrangementUnvestedRSUsLessSharesWithheldForApplicableTaxesMember_019c766a-a786-7617-b37f-4179cd03ed4f" xlink:type="arc" order="4"/>
  </link:definitionLink>
</link:linkbase>
