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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019fec57-5315-7505-9b8e-838859b82e23,g:cc30d394-e234-4195-b19a-3142e306c51c-->
<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://texascapitalbank.com/role/DocumentAndEntityInformationDocument" xlink:type="simple" xlink:href="tcbi-20261021.xsd#DocumentAndEntityInformationDocument"/>
  <link:definitionLink xlink:role="http://texascapitalbank.com/role/DocumentAndEntityInformationDocument" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInformationLineItems_019fec57-5315-7e36-b2f3-fd9f6af3f56f" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitiesTable_019fec57-5315-7bbe-b52d-8d6deefcdb77" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntitiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_EntityInformationLineItems_019fec57-5315-7e36-b2f3-fd9f6af3f56f" xlink:to="loc_dei_EntitiesTable_019fec57-5315-7bbe-b52d-8d6deefcdb77" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019fec57-5315-7ca1-8d7f-460bffa3867f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_019fec57-5315-7bbe-b52d-8d6deefcdb77" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019fec57-5315-7ca1-8d7f-460bffa3867f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019fec57-5315-7ca1-8d7f-460bffa3867f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019fec57-5315-7ca1-8d7f-460bffa3867f" xlink:to="loc_us-gaap_ClassOfStockDomain_019fec57-5315-7ca1-8d7f-460bffa3867f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019fec57-5315-700b-809f-89aacced4406" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019fec57-5315-7ca1-8d7f-460bffa3867f" xlink:to="loc_us-gaap_ClassOfStockDomain_019fec57-5315-700b-809f-89aacced4406" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_019fec57-5315-7d1e-89be-516088c4faea" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019fec57-5315-700b-809f-89aacced4406" xlink:to="loc_us-gaap_CommonStockMember_019fec57-5315-7d1e-89be-516088c4faea" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesBPreferredStockMember_019fec57-5315-762a-83dc-015b69d4ced8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeriesBPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019fec57-5315-700b-809f-89aacced4406" xlink:to="loc_us-gaap_SeriesBPreferredStockMember_019fec57-5315-762a-83dc-015b69d4ced8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_019fec57-5315-778b-8dbf-6c3f637c9eb2" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityRegistrantName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fec57-5315-7e36-b2f3-fd9f6af3f56f" xlink:to="loc_dei_EntityRegistrantName_019fec57-5315-778b-8dbf-6c3f637c9eb2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_019fec57-5315-72cc-a100-3ea87bbdc924" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fec57-5315-7e36-b2f3-fd9f6af3f56f" xlink:to="loc_dei_EntityEmergingGrowthCompany_019fec57-5315-72cc-a100-3ea87bbdc924" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_019fec57-5315-7edb-964f-7332b91b40bf" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_Security12bTitle"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fec57-5315-7e36-b2f3-fd9f6af3f56f" xlink:to="loc_dei_Security12bTitle_019fec57-5315-7edb-964f-7332b91b40bf" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_019fec57-5315-77df-91ae-0c73960213e7" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_TradingSymbol"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fec57-5315-7e36-b2f3-fd9f6af3f56f" xlink:to="loc_dei_TradingSymbol_019fec57-5315-77df-91ae-0c73960213e7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_019fec57-5315-7f3a-a4be-cc0ec6fe38c2" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fec57-5315-7e36-b2f3-fd9f6af3f56f" xlink:to="loc_dei_EntityIncorporationStateCountryCode_019fec57-5315-7f3a-a4be-cc0ec6fe38c2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_WrittenCommunications_019fec57-5315-76f9-8170-811f571da5f3" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_WrittenCommunications"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fec57-5315-7e36-b2f3-fd9f6af3f56f" xlink:to="loc_dei_WrittenCommunications_019fec57-5315-76f9-8170-811f571da5f3" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_019fec57-5315-7ce7-9cfe-89cf070a4a70" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentType"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fec57-5315-7e36-b2f3-fd9f6af3f56f" xlink:to="loc_dei_DocumentType_019fec57-5315-7ce7-9cfe-89cf070a4a70" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_019fec57-5316-749a-8004-d7955132e94e" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentPeriodEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fec57-5315-7e36-b2f3-fd9f6af3f56f" xlink:to="loc_dei_DocumentPeriodEndDate_019fec57-5316-749a-8004-d7955132e94e" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_019fec57-5316-78d9-96d7-5687169220b2" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressAddressLine1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fec57-5315-7e36-b2f3-fd9f6af3f56f" xlink:to="loc_dei_EntityAddressAddressLine1_019fec57-5316-78d9-96d7-5687169220b2" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine2_019fec57-5316-7cac-96ca-56a4ab134da4" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressAddressLine2"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fec57-5315-7e36-b2f3-fd9f6af3f56f" xlink:to="loc_dei_EntityAddressAddressLine2_019fec57-5316-7cac-96ca-56a4ab134da4" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_019fec57-5316-764a-9baf-af9bb26a35b7" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressCityOrTown"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fec57-5315-7e36-b2f3-fd9f6af3f56f" xlink:to="loc_dei_EntityAddressCityOrTown_019fec57-5316-764a-9baf-af9bb26a35b7" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_019fec57-5316-7160-968c-d4da3d2d0a39" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressStateOrProvince"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fec57-5315-7e36-b2f3-fd9f6af3f56f" xlink:to="loc_dei_EntityAddressStateOrProvince_019fec57-5316-7160-968c-d4da3d2d0a39" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_019fec57-5316-77c0-a81b-f2d2c394303c" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressPostalZipCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fec57-5315-7e36-b2f3-fd9f6af3f56f" xlink:to="loc_dei_EntityAddressPostalZipCode_019fec57-5316-77c0-a81b-f2d2c394303c" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_019fec57-5316-710b-99bb-aa6d4025cb4d" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_CityAreaCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fec57-5315-7e36-b2f3-fd9f6af3f56f" xlink:to="loc_dei_CityAreaCode_019fec57-5316-710b-99bb-aa6d4025cb4d" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_019fec57-5316-7f97-97d2-368fbab46de4" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_LocalPhoneNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fec57-5315-7e36-b2f3-fd9f6af3f56f" xlink:to="loc_dei_LocalPhoneNumber_019fec57-5316-7f97-97d2-368fbab46de4" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SolicitingMaterial_019fec57-5316-712f-a85d-91863cff8c1c" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_SolicitingMaterial"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fec57-5315-7e36-b2f3-fd9f6af3f56f" xlink:to="loc_dei_SolicitingMaterial_019fec57-5316-712f-a85d-91863cff8c1c" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementTenderOffer_019fec57-5316-7f52-bc30-15ed850621eb" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_PreCommencementTenderOffer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fec57-5315-7e36-b2f3-fd9f6af3f56f" xlink:to="loc_dei_PreCommencementTenderOffer_019fec57-5316-7f52-bc30-15ed850621eb" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementIssuerTenderOffer_019fec57-5316-7907-8e37-81605ece3656" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_PreCommencementIssuerTenderOffer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fec57-5315-7e36-b2f3-fd9f6af3f56f" xlink:to="loc_dei_PreCommencementIssuerTenderOffer_019fec57-5316-7907-8e37-81605ece3656" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_019fec57-5316-7c16-bfe5-e7cd7b1de55b" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityFileNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fec57-5315-7e36-b2f3-fd9f6af3f56f" xlink:to="loc_dei_EntityFileNumber_019fec57-5316-7c16-bfe5-e7cd7b1de55b" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_019fec57-5316-71bf-bedd-8b19e37fd662" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fec57-5315-7e36-b2f3-fd9f6af3f56f" xlink:to="loc_dei_EntityTaxIdentificationNumber_019fec57-5316-71bf-bedd-8b19e37fd662" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_019fec57-5316-71b5-a527-8e44278d945d" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_SecurityExchangeName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fec57-5315-7e36-b2f3-fd9f6af3f56f" xlink:to="loc_dei_SecurityExchangeName_019fec57-5316-71b5-a527-8e44278d945d" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_019fec57-5316-7411-a2d3-bddc416c68c5" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityCentralIndexKey"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fec57-5315-7e36-b2f3-fd9f6af3f56f" xlink:to="loc_dei_EntityCentralIndexKey_019fec57-5316-7411-a2d3-bddc416c68c5" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_019fec57-5316-71fd-8978-83618c0f9dd4" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_AmendmentFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fec57-5315-7e36-b2f3-fd9f6af3f56f" xlink:to="loc_dei_AmendmentFlag_019fec57-5316-71fd-8978-83618c0f9dd4" xlink:type="arc" order="22"/>
  </link:definitionLink>
</link:linkbase>
