You can't directly block someone, but if they claim your child, your e-filed return will reject, requiring you to mail a paper return, and the IRS will sort it out by sending letters and requiring proof (like school records) to determine the rightful claimant, usually the custodial parent, who then must follow IRS instructions to potentially amend or face repayment with penalties.
If someone claims your child on taxes, first paper file your return (as e-filing gets rejected) and the IRS will investigate, sending letters to both parties to determine who's eligible, which can take time and delay refunds. If it's identity theft, report it to IdentityTheft.gov and IRS.gov and file Form 14039, Identity Theft Affidavit; for fraud by a known person (like an ex), you might use Form 3949-A.
If a non-custodial parent claims a child on their taxes without permission, the IRS usually flags it, forcing the custodial parent to file a paper return, eventually assigning benefits to the rightful parent (usually the custodian) and potentially triggering an audit for both parents, leading to penalties and interest for the non-custodial parent, who must repay any wrongly claimed refunds, as determined by the court order or custody arrangement.
File Early: Filing or e-filing your tax return early can help prevent someone else from claiming your dependent before you do.
What Happens When Both Parents Claim a Child on a Tax Return? If you file amended returns to claim the child, the IRS will intervene and if he was not the custodial parent, he will likely be required to amend his returns and pay back any credits he did not qualify for.
Yes, the IRS knows who the custodial parent is based on who the child lived with for more than half the year (more nights), but parents "self-certify" this when they file, with the custodial parent usually claiming the child unless a Form 8332 is signed to release the claim to the noncustodial parent, who then attaches it to their return. If a dispute arises or both claim the child, the IRS uses tie-breaker rules (higher AGI for equal time) and can request documentation like school records or medical bills to determine the rightful claimant.
Determining who can claim a child (usually for tax purposes) depends on residency, relationship, and support, but for divorced/separated parents, the custodial parent (who the child lives with more nights) generally claims the child, though the noncustodial parent can claim them if the custodial parent signs Form 8332, releasing the claim. Both parents must meet general IRS tests for a qualifying child, including age, relationship, residency (more than half the year), and support (child provides less than half their own support).
If you are the custodial parent, you can use Form 8332 to do the following. Release a claim to exemption for your child so that the noncustodial parent can claim an exemption for the child. Revoke a previous release of claim to exemption for your child.
You may receive a letter (CP87A) from us, stating your child was claimed on another return. It will explain what to do, either file an amended return or do nothing. The other person who claimed the dependent will get the same letter.
Without a court order, both parents have an equal say in major decisions affecting the children. However, this doesn't necessarily mean that your ex can dictate everything about who you introduce to the children, unless she can demonstrate that your new partner poses a risk to their welfare.
Next tax year: Protect your dependent with an IP-PIN (Identity Protection - Personal Identification Number). This will prevent any unauthorized person (ex-spouse, partner, family member) from e-filing a tax return and claiming your qualified dependent.
The Custody Ratio Tiebreaker
Under these rules, the parent who has physical custody of the child for the greater part of the year – defined as more than 50% of the nights – typically has the right to claim the child as a dependent for tax purposes.
Yes, a noncustodial parent (NCP) can claim a child on their 2025 taxes, but only if the custodial parent (CP) provides written consent, typically using IRS Form 8332, releasing their claim to the child as a dependent for specific tax benefits like the Child Tax Credit and dependency exemption. The CP generally retains rights to other credits, like the Earned Income Credit (EITC) and Head of Household filing status.
If the child is yours, proving the relationship is usually as simple as providing the child's birth certificate. If it is a grandchild, sibling, niece, or nephew, you may also have to show the birth certificate of the child's parent and your birth certificate to prove the relationship.
Make sure your dependent meets the IRS requirements. Generally, the IRS requires that the child is under the age of 19 (or under 24 if a full-time student), lives with you for more than half the year, and does not provide more than half of their own financial support.
If a non-custodial parent claims a child on their taxes without permission, the IRS usually flags it, forcing the custodial parent to file a paper return, eventually assigning benefits to the rightful parent (usually the custodian) and potentially triggering an audit for both parents, leading to penalties and interest for the non-custodial parent, who must repay any wrongly claimed refunds, as determined by the court order or custody arrangement.
Generally, the child is the qualifying child of the custodial parent. The custodial parent is the parent with whom the child lived for the longer period of time during the year.
The IRS determines the custodial parent primarily by who the child lives with for the greater number of nights in the year (more than half, or 183+ nights), not by legal custody documents, although parents can agree to shift the claim using Form 8332, notes IRS.gov. If the child spends an equal number of nights with each parent, the parent with the higher Adjusted Gross Income (AGI) becomes the custodial parent for tax purposes, applying tiebreaker rules.
Claiming a child who does not meet the qualifying child requirements. Filing with an incorrect filing status. Overreporting or underreporting income and expenses. Having more than one person claiming the same child.