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

    <schemaVersion>X0305</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2012-06-19</periodOfReport>

    <issuer>
        <issuerCik>0000700863</issuerCik>
        <issuerName>SUSQUEHANNA BANCSHARES INC</issuerName>
        <issuerTradingSymbol>SUSQ</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001183477</rptOwnerCik>
            <rptOwnerName>QUICK MICHAEL M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>SUSQUEHANNA BANCSHARES, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>26 N. CEDAR STREET</rptOwnerStreet2>
            <rptOwnerCity>LITITZ</rptOwnerCity>
            <rptOwnerState>PA</rptOwnerState>
            <rptOwnerZipCode>17543</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isOfficer>1</isOfficer>
            <officerTitle>EVP &amp; Chief Corp. Credit Off.</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2012-06-19</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>25000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>25000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>25000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Each restricted stock unit represents a contingent right to receive one share of Susquehanna Bancshares, Inc. common stock.  Grant made under and subject to the terms of the Susquehanna Bancshares, Inc. Amended and Restated 2005 Equity Compensation Plan.</footnote>
        <footnote id="F2">The restricted stock units vest one third on each of December 31, 2012, December 31, 2013, and December 31, 2014 (each a &quot;Vesting Date&quot;); provided that (i) the executive continues to be employed by, or provide a service to, Susquehanna Bancshares, Inc. through the Vesting Date, and (ii) the Susquehanna Bancshares, Inc. Profit Trigger (as defined in the grant agreement governing the restricted stock unit grant) is achieved.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Carl D. Lundblad, attorney-in-fact for Michael M. Quick</signatureName>
        <signatureDate>2012-06-21</signatureDate>
    </ownerSignature>
</ownershipDocument>
