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

    <schemaVersion>X0304</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2011-11-01</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001080014</issuerCik>
        <issuerName>THERAVANCE INC</issuerName>
        <issuerTradingSymbol>THRX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001131399</rptOwnerCik>
            <rptOwnerName>GLAXOSMITHKLINE PLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>980 GREAT WEST ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BRENTFORD MIDDLESEX</rptOwnerCity>
            <rptOwnerState>X0</rptOwnerState>
            <rptOwnerZipCode>TW8 9GS</rptOwnerZipCode>
            <rptOwnerStateDescription>UNITED KINGDOM</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>2011-11-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>58411</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>22.23</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>15725953</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Corporation</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Common Stock purchased pursuant to the right of GlaxoSmithKline LLC (&quot;GSK LLC&quot;) under Section 2.1(d)(ii) of the Amended and Restated Governance Agreement by and among Theravance, Inc. (the &quot;Issuer&quot;), GSK LLC, Glaxo Group Limited and GlaxoSmithKline plc dated as of June 4, 2004, as amended. Pursuant to Section 2.1(d)(ii), GSK LLC has the right to purchase from the Issuer, on a quarterly basis, sufficient shares of common stock to maintain its ownership percentage in the Issuer taking into account the preceding quarter's option exercise and equity vesting activity.</footnote>
        <footnote id="F2">Shares of Common Stock are held of record by Glaxo Group Limited.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Victoria Whyte, Company Secretary</signatureName>
        <signatureDate>2011-11-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
