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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2013-07-30</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001313911</issuerCik>
        <issuerName>Rally Software Development Corp</issuerName>
        <issuerTradingSymbol>RALY</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001573549</rptOwnerCik>
            <rptOwnerName>Leavitt Richard D</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O RALLY SOFTWARE DEVELOPMENT CORP.</rptOwnerStreet1>
            <rptOwnerStreet2>3333 WALNUT STREET</rptOwnerStreet2>
            <rptOwnerCity>BOULDER</rptOwnerCity>
            <rptOwnerState>CO</rptOwnerState>
            <rptOwnerZipCode>80301</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>EVP, Worldwide Marketing</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2013-07-30</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>20000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>23.5373</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>43500</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Includes 4,500 previously reported shares issued as restricted stock units (&quot;RSUs&quot;) under the Issuer's 2013 Equity Incentive Plan (the &quot;Plan&quot;) that were received as an award, for no consideration. The RSUs vest in a series of four successive annual installments beginning on June 28, 2013, provided in each case that the Reporting Person's continuous service to the Issuer has not been terminated as defined in or as determined under the Plan.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ James M. Lejeal, Attorney-in-Fact</signatureName>
        <signatureDate>2013-08-01</signatureDate>
    </ownerSignature>
</ownershipDocument>
