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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2015-08-13</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>2015-08-13</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"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>8734</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">On August 13, 2015, Bessemer Venture Partners VII, L.P. (&quot;BVP VII&quot;) sold 104,000 shares of Common Stock of the Issuer (the &quot;shares&quot;), Bessemer Venture Partners VII Institutional L.P. (&quot;BVP VII Inst&quot;) sold  45,500 shares, 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 175,500 shares at a price of $37.50.  After the sales, BVP VII owned 498,578 shares, BVP VII Inst owned 218,127 shares, and BVP VII SOF owned 841,352 shares.  The shares were sold in one execution that took place at $37.50. The Reporting Person hereby undertakes, upon request of the Staff of the U.S. Securities and Exchange Commission, the Issuer or a security holder of the Issuer, to provide full information regarding such execution.</footnote>
        <footnote id="F2">Represents restricted stock units held directly by the reporting person. Each restricted stock unit represents a contingent right to receive one share of common stock of the issuer.</footnote>
        <footnote id="F3">The reporting person is a director of Deer VII &amp; Co. Ltd, which is the general partner of Deer VII &amp; Co. L.P., 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 &amp; Co. Ltd., his interest in Deer VII &amp; Co. L.P. 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>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Robert M. Stavis</signatureName>
        <signatureDate>2015-08-17</signatureDate>
    </ownerSignature>
</ownershipDocument>
