A child or other relative who is claimed as a dependent by one taxpayer can’t be claimed as a dependent by any other taxpayer in the same tax year, says the Internal Revenue Service (IRS) in Publication 501, Exemptions & Dependents, published at IRS.gov. If that dependent files his own income tax return, he can’t claim exemptions for himself or his own dependents if he’s already being claimed as a dependent by someone else.
Joint Return Issues
The IRS dependent-claiming rules can sometimes be tricky for married couples filing jointly. The IRS says you normally can't claim a married child as a dependent if he files a joint tax return, even if he meets dependency tests. The sole exception is if he filed a joint return only to claim a tax refund and neither spouse would have a tax liability if they filed separate returns. But if the child files a joint return with a spouse who is being claimed as someone else's dependent, then the couple loses all personal and dependent exemptions, which could create a tax liability where none existed before.
If a child or other relative could be claimed as a dependent by two different taxpayers, the IRS says only one of the taxpayers can take the dependency exemption, child tax credit, earned income credit, child care credit or other dependency tax benefits. It’s an all-or-nothing proposition. The two contending taxpayers can’t make any agreement to split the tax benefits between them. Married couples filing jointly count as one taxpayer, so this issue doesn’t arise for them.
The IRS has tiebreaker rules for determining who can claim a dependent in the event of a conflict. If each contending party is a separated parent of the dependent, the tax break goes to the parent with whom the child lived longest. If residency was equal, then the parent with the highest adjusted gross income gets the dependency tax breaks. If one of the parties is the dependent’s parent and the other is not a parent, the tax break goes to the parent, says the IRS. If no parent has claimed the child as a dependent, or if the contending parents were never married, the tax benefits go to the contending claimant with the highest adjusted gross income.
If a household has multiple dependents and multiple taxpayers who could claim them, the rule against multiple taxpayers claiming the same dependent still applies, says the IRS. Each dependent can be claimed by only one of the household’s taxpayers, but one of the taxpayers could claim two or more of the dependents as a qualifying child or relative. The IRS tiebreaker rules could help them determine which taxpayer claims which dependent.