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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2021-12-28</periodOfReport>

    <issuer>
        <issuerCik>0001314152</issuerCik>
        <issuerName>Jones Lang LaSalle Income Property Trust, Inc.</issuerName>
        <issuerTradingSymbol>1314152</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001234117</rptOwnerCik>
            <rptOwnerName>Breen Virginia G</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>333 W. WACKER DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CHICAGO</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60606</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class M-I Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-12-28</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>252.664</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>13.57</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>20523.435</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class M-I Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2022-03-25</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F2"/>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>247.315</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>14.52</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>20770.75</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Shares acquired pursuant to the Jones Lang LaSalle Income Property Trust, Inc. Amended and Restated Distribution Reinvestment Plan on December 28, 2021 which were previously not reported: On December 28, 2021 acquired 252.6640 shares at $13.57 per share.</footnote>
        <footnote id="F2">Shares acquired pursuant to the Jones Lang LaSalle Income Property Trust, Inc. Amended and Restated Distribution Reinvestment Plan on March 25, 2022.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Gordon G. Repp, attorney-in-fact for Virginia G. Breen</signatureName>
        <signatureDate>2022-03-29</signatureDate>
    </ownerSignature>
</ownershipDocument>
