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    <isConfidential>false</isConfidential>
    <filerInfo>

      <filer>
        <issuerCredentials>
          <cik>0000355437</cik>
          <ccc>XXXXXXXX</ccc>
        </issuerCredentials>
      </filer>


      <seriesClassInfo>
        <seriesId>S000000967</seriesId>
        <classId>C000002718</classId>
      </seriesClassInfo>


    </filerInfo>
  </headerData>
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      <regName>DFA INVESTMENT DIMENSIONS GROUP INC</regName>
      <regFileNumber>811-03258</regFileNumber>
      <regCik>0000355437</regCik>
      <regLei>549300XGRTBJCE41BD26</regLei>
      <regStreet1>6300 BEE CAVE ROAD</regStreet1>
      <regStreet2>BUILDING ONE</regStreet2>
      <regCity>AUSTIN</regCity>
      <regStateConditional regCountry="US" regState="US-TX"/>
      <regZipOrPostalCode>78746</regZipOrPostalCode>
      <regPhone>512-306-7400</regPhone>
      <seriesName>INTERNATIONAL SMALL COMPANY PORTFOLIO</seriesName>
      <seriesId>S000000967</seriesId>
      <seriesLei>5493001J4NVI3L3AP896</seriesLei>
      <repPdEnd>2026-10-31</repPdEnd>
      <repPdDate>2026-07-31</repPdDate>
      <isFinalFiling>N</isFinalFiling>
    </genInfo>
    <fundInfo>
      <totAssets>16047143562.56</totAssets>
      <totLiabs>4043341.28</totLiabs>
      <netAssets>16043100221.28</netAssets>
      <assetsAttrMiscSec>0.00000000</assetsAttrMiscSec>
      <assetsInvested>0.00000000</assetsInvested>
      <amtPayOneYrBanksBorr>0.00000000</amtPayOneYrBanksBorr>
      <amtPayOneYrCtrldComp>0.00000000</amtPayOneYrCtrldComp>
      <amtPayOneYrOthAffil>0.00000000</amtPayOneYrOthAffil>
      <amtPayOneYrOther>0.00000000</amtPayOneYrOther>
      <amtPayAftOneYrBanksBorr>0.00000000</amtPayAftOneYrBanksBorr>
      <amtPayAftOneYrCtrldComp>0.00000000</amtPayAftOneYrCtrldComp>
      <amtPayAftOneYrOthAffil>0.00000000</amtPayAftOneYrOthAffil>
      <amtPayAftOneYrOther>0.00000000</amtPayAftOneYrOther>
      <delayDeliv>0.00000000</delayDeliv>
      <standByCommit>0.00000000</standByCommit>
      <liquidPref>0.00000000</liquidPref>
      <cshNotRptdInCorD>10220928.11000000</cshNotRptdInCorD>
      <isNonCashCollateral>N</isNonCashCollateral>
      <returnInfo>
        <monthlyTotReturns>
          <monthlyTotReturn classId="C000002718" rtn1="2.96000000" rtn2="-3.36000000" rtn3="2.08000000"/>
        </monthlyTotReturns>
        <monthlyReturnCats>
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            <mon2 netRealizedGain="13034064.78000000" netUnrealizedAppr="-14016600.47000000"/>
            <mon3 netRealizedGain="254007.68000000" netUnrealizedAppr="-1139788.73000000"/>
            <futureCategory>
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        <othMon2 netRealizedGain="0.00000000" netUnrealizedAppr="0.00000000"/>
        <othMon3 netRealizedGain="0.00000000" netUnrealizedAppr="0.00000000"/>
      </returnInfo>
      <mon1Flow redemption="234886415.29000000" reinvestment="0.00000000" sales="188934530.02000000"/>
      <mon2Flow redemption="201691923.40000000" reinvestment="159732232.67000000" sales="217617333.44000000"/>
      <mon3Flow redemption="169266185.75000000" reinvestment="0.00000000" sales="203875351.39000000"/>


    </fundInfo>
    <invstOrSecs>
      <invstOrSec>
        <name>State Street Global Advisors</name>
        <lei>549300BZ5TGIFZUZDZ37</lei>
        <title>State Street Institutional U.S. Government Money Market Fund</title>
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        <identifiers>
          <isin value="US8574927062"/>
        </identifiers>
        <balance>153416051.15000000</balance>
        <units>NS</units>
        <curCd>USD</curCd>
        <valUSD>153416051.15000000</valUSD>
        <pctVal>0.956274342452</pctVal>
        <payoffProfile>Long</payoffProfile>
        <assetCat>STIV</assetCat>
        <issuerCat>RF</issuerCat>
        <invCountry>US</invCountry>
        <isRestrictedSec>N</isRestrictedSec>

        <fairValLevel>1</fairValLevel>
        <securityLending>
          <isCashCollateral>N</isCashCollateral>
          <isNonCashCollateral>N</isNonCashCollateral>
          <isLoanByFund>N</isLoanByFund>
        </securityLending>
      </invstOrSec>
      <invstOrSec>
        <name>Chicago Mercantile Exchange</name>
        <lei>SNZ2OJLFK8MNNCLQOF39</lei>
        <title>S+P500 EMINI FUT SEP26</title>
        <cusip>000000000</cusip>
        <identifiers>
          <other otherDesc="Bloomberg Identifier" value="BBG01HZQ8JX9"/>
        </identifiers>
        <balance>398.00000000</balance>
        <units>NC</units>
        <curCd>USD</curCd>
        <valUSD>700311.45000000</valUSD>
        <pctVal>0.004365187777</pctVal>
        <payoffProfile>N/A</payoffProfile>
        <assetCat>DE</assetCat>
        <issuerConditional desc="derivative" issuerCat="OTHER"/>
        <invCountry>US</invCountry>
        <isRestrictedSec>N</isRestrictedSec>

        <fairValLevel>1</fairValLevel>
        <derivativeInfo>
          <futrDeriv derivCat="FUT">
            <counterparties>
              <counterpartyName>Chicago Mercantile Exchange</counterpartyName>
              <counterpartyLei>SNZ2OJLFK8MNNCLQOF39</counterpartyLei>
            </counterparties>
            <payOffProf>Long</payOffProf>
            <descRefInstrmnt>
              <indexBasketInfo>
                <indexName>CME E-mini S&amp;P 500 Index Futures</indexName>
                <indexIdentifier>ESU6 Index</indexIdentifier>
              </indexBasketInfo>
            </descRefInstrmnt>
            <expDate>2026-09-18</expDate>
            <notionalAmt>148932763.55000000</notionalAmt>
            <curCd>USD</curCd>
            <unrealizedAppr>700311.45000000</unrealizedAppr>
          </futrDeriv>
        </derivativeInfo>
        <securityLending>
          <isCashCollateral>N</isCashCollateral>
          <isNonCashCollateral>N</isNonCashCollateral>
          <isLoanByFund>N</isLoanByFund>
        </securityLending>
      </invstOrSec>
      <invstOrSec>
        <name>Dimensional Fund Advisors</name>
        <lei>54930006OMTUF18TBS36</lei>
        <title>THE CANADIAN SMALL COMPANY SERIES</title>
        <cusip>000000000</cusip>
        <identifiers>
          <other otherDesc="Internal Identifier" value="DFAE_MASTER"/>
        </identifiers>
        <balance>57123608.06000000</balance>
        <units>NS</units>
        <curCd>USD</curCd>
        <valUSD>2006752351.00000000</valUSD>
        <pctVal>12.50850722940</pctVal>
        <payoffProfile>Long</payoffProfile>
        <assetCat>EC</assetCat>
        <issuerCat>RF</issuerCat>
        <invCountry>US</invCountry>
        <isRestrictedSec>N</isRestrictedSec>

        <fairValLevel>N/A</fairValLevel>
        <securityLending>
          <isCashCollateral>N</isCashCollateral>
          <isNonCashCollateral>N</isNonCashCollateral>
          <isLoanByFund>N</isLoanByFund>
        </securityLending>
      </invstOrSec>
      <invstOrSec>
        <name>Dimensional Fund Advisors</name>
        <lei>549300TTGDINCXXSVF04</lei>
        <title>THE CONTINENTAL SMALL COMPANY SERIES</title>
        <cusip>000000000</cusip>
        <identifiers>
          <other otherDesc="Internal Identifier" value="DFAF_MASTER"/>
        </identifiers>
        <balance>36008412.59000000</balance>
        <units>NS</units>
        <curCd>USD</curCd>
        <valUSD>6745816014.00000000</valUSD>
        <pctVal>42.04808248378</pctVal>
        <payoffProfile>Long</payoffProfile>
        <assetCat>EC</assetCat>
        <issuerCat>RF</issuerCat>
        <invCountry>US</invCountry>
        <isRestrictedSec>N</isRestrictedSec>

        <fairValLevel>N/A</fairValLevel>
        <securityLending>
          <isCashCollateral>N</isCashCollateral>
          <isNonCashCollateral>N</isNonCashCollateral>
          <isLoanByFund>N</isLoanByFund>
        </securityLending>
      </invstOrSec>
      <invstOrSec>
        <name>Dimensional Fund Advisors</name>
        <lei>549300CBGM4U9R4DEL16</lei>
        <title>THE ASIA PACIFIC SMALL COMPANY SERIES</title>
        <cusip>000000000</cusip>
        <identifiers>
          <other otherDesc="Internal Identifier" value="DFAH_MASTER"/>
        </identifiers>
        <balance>21117490.34000000</balance>
        <units>NS</units>
        <curCd>USD</curCd>
        <valUSD>1478224324.00000000</valUSD>
        <pctVal>9.214081465621</pctVal>
        <payoffProfile>Long</payoffProfile>
        <assetCat>EC</assetCat>
        <issuerCat>RF</issuerCat>
        <invCountry>US</invCountry>
        <isRestrictedSec>N</isRestrictedSec>

        <fairValLevel>N/A</fairValLevel>
        <securityLending>
          <isCashCollateral>N</isCashCollateral>
          <isNonCashCollateral>N</isNonCashCollateral>
          <isLoanByFund>N</isLoanByFund>
        </securityLending>
      </invstOrSec>
      <invstOrSec>
        <name>Dimensional Fund Advisors</name>
        <lei>549300FCYEDRJO2L0O02</lei>
        <title>THE UNITED KINGDOM SMALL COMPANY SERIES</title>
        <cusip>000000000</cusip>
        <identifiers>
          <other otherDesc="Internal Identifier" value="DFAI_MASTER"/>
        </identifiers>
        <balance>16885292.25000000</balance>
        <units>NS</units>
        <curCd>USD</curCd>
        <valUSD>1925936434.00000000</valUSD>
        <pctVal>12.00476471153</pctVal>
        <payoffProfile>Long</payoffProfile>
        <assetCat>EC</assetCat>
        <issuerCat>RF</issuerCat>
        <invCountry>US</invCountry>
        <isRestrictedSec>N</isRestrictedSec>

        <fairValLevel>N/A</fairValLevel>
        <securityLending>
          <isCashCollateral>N</isCashCollateral>
          <isNonCashCollateral>N</isNonCashCollateral>
          <isLoanByFund>N</isLoanByFund>
        </securityLending>
      </invstOrSec>
      <invstOrSec>
        <name>Dimensional Fund Advisors</name>
        <lei>549300XCLYJKZX2XQ177</lei>
        <title>THE JAPANESE SMALL COMPANY SERIES</title>
        <cusip>000000000</cusip>
        <identifiers>
          <other otherDesc="Internal Identifier" value="DFAJ_MASTER"/>
        </identifiers>
        <balance>109121649.20000000</balance>
        <units>NS</units>
        <curCd>USD</curCd>
        <valUSD>3725413103.00000000</valUSD>
        <pctVal>23.22127925161</pctVal>
        <payoffProfile>Long</payoffProfile>
        <assetCat>EC</assetCat>
        <issuerCat>RF</issuerCat>
        <invCountry>US</invCountry>
        <isRestrictedSec>N</isRestrictedSec>

        <fairValLevel>N/A</fairValLevel>
        <securityLending>
          <isCashCollateral>N</isCashCollateral>
          <isNonCashCollateral>N</isNonCashCollateral>
          <isLoanByFund>N</isLoanByFund>
        </securityLending>
      </invstOrSec>
    </invstOrSecs>
    <explntrNotes>
      <explntrNote note="Monthly returns presented in Item B.5(a) have been calculated without deducting any applicable sales loads or redemption fees." noteItem="B.5.a"/>
    </explntrNotes>
    <signature>
      <ncom:dateSigned>2026-08-31</ncom:dateSigned>
      <ncom:nameOfApplicant>DFA INVESTMENT DIMENSIONS GROUP INC</ncom:nameOfApplicant>
      <ncom:signature>Randy Olson</ncom:signature>
      <ncom:signerName>Randy Olson</ncom:signerName>
      <ncom:title>Vice President</ncom:title>
    </signature>
  </formData>
  <documents>XXXX</documents>
</edgarSubmission>
