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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2015-09-03</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001459417</issuerCik>
        <issuerName>2U, Inc.</issuerName>
        <issuerTradingSymbol>TWOU</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001241953</rptOwnerCik>
            <rptOwnerName>STAVIS ROBERT M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O BESSEMER VENTURE PARTNERS</rptOwnerStreet1>
            <rptOwnerStreet2>1865 PALMER AVENUE, SUITE 104</rptOwnerStreet2>
            <rptOwnerCity>LARCHMONT</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10538</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2015-09-03</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>0</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Funds</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>39648</value>
                    <footnoteId id="F5"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F5"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">On September 3, 2015, Deer VII &amp; Co. L.P. (&quot;Deer VII&quot;), the general partner of Bessemer Venture Partners VII, L.P. (&quot;BVP VII&quot;), Bessemer Venture Partners VII Institutional L.P. (&quot;BVP VII Inst&quot;), and BVP VII Special Opportunity Fund L.P. (&quot;BVP VII SOF,&quot; and together with BVP VII and BVP VII Inst, the &quot;Funds&quot;) sold an aggregate of 11,038 shares of Common Stock of the Issuer (the &quot;shares&quot;) at the weighted average sale price of $35.0002.  The shares sold were received by Deer VII in distributions-in-kind by the Funds, which distributions were made in accordance with the exemption afforded by Rules 16a-9 and 16a-13 of the Securities Exchange Act of 1934, as amended (the &quot;DIKs&quot;).</footnote>
        <footnote id="F2">(continued from footnote 1) The shares were sold in multiple transactions at prices ranging from $35.050 to $35.260.  The reporting person undertakes to provide to the issuer, any security holder of the issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.</footnote>
        <footnote id="F3">After the above transaction, BVP VII owned 498,578 shares, BVP VII Inst owned 218,127 shares, and BVP VII SOF owned 841,352 shares.  Deer VII held no shares.</footnote>
        <footnote id="F4">The reporting person is a director of Deer VII &amp; Co. Ltd. (&quot;Deer VII Ltd&quot;), which is the general partner of Deer VII, which is the general partner of the Funds.  The reporting person disclaims beneficial ownership of the securities held by the Funds, except to the extent of his pecuniary interest, if any, in such securities by virtue of his interest in Deer VII Ltd, his interest in Deer VII, and his indirect limited partnership interest in the Funds. This report shall not be deemed an admission that the reporting person is the beneficial owner of such securities.</footnote>
        <footnote id="F5">The amount reported consists of 8,734 restricted stock units, each of which represents a contingent right to receive one share of common stock of the issuer, and shares of common stock of the issuer, which were received in the DIKs.  The restricted stock units are held directly by the reporting person.  8,545 of the shares are held directly by the reporting person, 10,847 of the shares are held by Stavis Ventures II, LLC, and the remaining 11,522 shares are held by Stavco Venture Holdings LLC.  These entities are controlled by the reporting person, and the reporting person disclaims beneficial ownership of the shares held by these entities, except to the extent of his pecuniary interest therein.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Robert M. Stavis</signatureName>
        <signatureDate>2015-09-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
