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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-06-01</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001207074</issuerCik>
        <issuerName>VIRTUSA CORP</issuerName>
        <issuerTradingSymbol>VRTU</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001406395</rptOwnerCik>
            <rptOwnerName>Holler Thomas R</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O VIRTUSA CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>2000 WEST PARK DRIVE</rptOwnerStreet2>
            <rptOwnerCity>WESTBOROUGH</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>01581</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>EVP and COO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-06-01</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2381</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>8.51</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>145615</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The reporting person was granted 120,000 shares of restricted stock under the Company's 2007 Stock Option and Incentive Plan on May 23, 2008 with a vesting commencement date of June 1, 2008.  12.5% of the restricted shares issued vested on June 1, 2008 with 6.25% of the restricted shares vesting each 3 month period thereafter in 14 equal installments.  On June 1, 2010, 6.25% of the shares (i.e., 7,500 shares) vested and the Company withheld via an automatic net exercise provision in the restricted stock award agreement 2,381 vested shares to satisfy the reporting person's tax obligations triggered as of the vesting date.</footnote>
        <footnote id="F2">Includes 11,250 shares of performance based restricted stock granted under the Company's 2007 Plan in October 2008, which vest only upon the Company's achievement of certain revenue and operating income targets for each fiscal year over the next three fiscal years, commencing with the fiscal year ending March 31, 2011.  The performance based restricted shares vest at a maximum of 3,750 shares per performance period upon achievement of applicable revenue and operating income targets for such fiscal year, with each fiscal year being a performance period.  The grantee retains voting rights with respect to such shares unless and to the extent that such shares do not vest and are forfeited.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Paul D. Tutun, Attorney in Fact</signatureName>
        <signatureDate>2010-06-02</signatureDate>
    </ownerSignature>
</ownershipDocument>
