<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2017-02-22</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001552033</issuerCik>
        <issuerName>TransUnion</issuerName>
        <issuerTradingSymbol>TRU</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001034196</rptOwnerCik>
            <rptOwnerName>ADVENT INTERNATIONAL CORP/MA</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ADVENT INTERNATIONAL CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>75 STATE STREET, 29TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02109</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001227759</rptOwnerCik>
            <rptOwnerName>ADVENT INTERNATIONAL LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ADVENT INTERNATIONAL CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>75 STATE STREET, 29TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02109</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001430919</rptOwnerCik>
            <rptOwnerName>ADVENT INTERNATIONAL GPE VI LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ADVENT INTERNATIONAL CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>75 STATE STREET, 29TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02109</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001430920</rptOwnerCik>
            <rptOwnerName>ADVENT INTERNATIONAL GPE VI-A LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ADVENT INTERNATIONAL CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>75 STATE STREET, 29TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02109</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001430926</rptOwnerCik>
            <rptOwnerName>ADVENT INTERNATIONAL GPE VI-B LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ADVENT INTERNATIONAL CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>75 STATE STREET, 29TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02109</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001430925</rptOwnerCik>
            <rptOwnerName>ADVENT INTERNATIONAL GPE VI-C LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ADVENT INTERNATIONAL CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>75 STATE STREET, 29TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02109</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001430923</rptOwnerCik>
            <rptOwnerName>ADVENT INTERNATIONAL GPE VI-D LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ADVENT INTERNATIONAL CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>75 STATE STREET, 29TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02109</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001430921</rptOwnerCik>
            <rptOwnerName>ADVENT INTERNATIONAL GPE VI-E LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ADVENT INTERNATIONAL CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>75 STATE STREET, 29TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02109</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001430922</rptOwnerCik>
            <rptOwnerName>ADVENT INTERNATIONAL GPE VI-F LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ADVENT INTERNATIONAL CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>75 STATE STREET, 29TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02109</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001432552</rptOwnerCik>
            <rptOwnerName>ADVENT INTERNATIONAL GPE VI-G LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ADVENT INTERNATIONAL CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>75 STATE STREET, 29TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02109</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2017-02-22</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>9730500</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>36.57</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>27727259</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Notes</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The shares of common stock of the Issuer were sold in connection with a secondary offering of the common stock of the Issuer pursuant to the prospectus supplement, dated February 15, 2017, and accompanying registration statement on Form S-3, dated September 8, 2016.</footnote>
        <footnote id="F2">Advent-TransUnion Acquisition Limited Partnership (&quot;ATUA&quot;) directly owns 27,727,259 shares of common stock of the Issuer. The Advent Funds (as defined below) directly own all of the partnership interests in ATUA. ATUA, together with Advent International Corporation (&quot;AIC&quot;), Advent International LLC (&quot;AILLC&quot;), GPE VI GP Limited Partnership (&quot;GPE VI GP&quot;), GPE VI GP (Delaware) Limited Partnership (&quot;GPE VI (DE) GP&quot;) and the Advent Funds, are referred to herein as the &quot;Reporting Persons&quot;. The shares directly owned by ATUA may be deemed beneficially owned by the other Reporting Persons; however, each Reporting Person disclaims beneficial ownership of these securities except to the extent of its respective pecuniary interest therein, if any, and the inclusion of these shares in their report shall not be deemed an admission of beneficial ownership of all of the reported shares for purposes of Section 16 or any other purpose.</footnote>
        <footnote id="F3">AIC is the manager of AILLC which is the general partner of each of GPE VI GP, GPE VI (DE) GP, Advent Partners GPE VI 2008 Limited Partnership, Advent Partners GPE VI 2009 Limited Partnership, Advent Partners GPE VI 2010 Limited Partnership, Advent Partners GPE VI-A Limited Partnership, and Advent Partners GPE VI-A 2010 Limited Partnership (collectively, the &quot;AP Funds&quot;).</footnote>
        <footnote id="F4">GPE VI (DE) GP is the general partner of the following entities: Advent International GPE VI-C Limited Partnership, Advent International GPE VI-D Limited Partnership and GPE VI-E Limited Partnership (collectively, the &quot;GPE VI (DE) GP Funds&quot;).</footnote>
        <footnote id="F5">GPE VI GP is the general partner of the following entities: Advent International GPE VI-G Limited Partnership, Advent International GPE VI Limited Partnership, Advent International GPE VI-A Limited Partnership, Advent Internal GPE VI-B Limited Partnership, and Advent International GPE VI-F Limited Partnership (collectively, the &quot;GPE GP Funds&quot; and together with the GPE VI (DE) GP Funds and the AP Funds, collectively the &quot;Advent Funds&quot;).</footnote>
    </footnotes>

    <remarks>This Form 4 is the first of two Forms 4 being filed relating to the same event.  The Form 4 has been split into two filings because there are more than 10 Reporting Persons in total, and the SEC's EDGAR filing system limits a single Form 4 to a maximum of 10 Reporting Persons.  Each Form 4 will be filed by Designated Filer Advent International Corporation.</remarks>

    <ownerSignature>
        <signatureName>/s/ Richard Terranova, as attorney-in-fact for Advent International Corp/MA</signatureName>
        <signatureDate>2017-02-23</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Richard Terranova, as attorney-in-fact for Advent International LLC</signatureName>
        <signatureDate>2017-02-23</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Richard Terranova, as attorney-in-fact for Advent International GPE VI Limited Partnership</signatureName>
        <signatureDate>2017-02-23</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Richard Terranova, as attorney-in-fact for Advent International GPE VI-A Limited Partnership</signatureName>
        <signatureDate>2017-02-23</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Richard Terranova, as attorney-in-fact for Advent International GPE VI-B Limited Partnership</signatureName>
        <signatureDate>2017-02-23</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Richard Terranova, as attorney-in-fact for Advent International GPE VI-C Limited Partnership</signatureName>
        <signatureDate>2017-02-23</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Richard Terranova, as attorney-in-fact for Advent International GPE VI-D Limited Partnership</signatureName>
        <signatureDate>2017-02-23</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Richard Terranova, as attorney-in-fact for Advent International GPE VI-E Limited Partnership</signatureName>
        <signatureDate>2017-02-23</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Richard Terranova, as attorney-in-fact for Advent International GPE VI-F Limited Partnership</signatureName>
        <signatureDate>2017-02-23</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Richard Terranova, as attorney-in-fact for Advent International GPE VI-G Limited Partnership</signatureName>
        <signatureDate>2017-02-23</signatureDate>
    </ownerSignature>
</ownershipDocument>
