If your ex claims your child on taxes and you’re entitled to that claim, the IRS will ultimately award the dependent to the parent the child actually lived with for more than half the year. In the meantime, your e-filed return will be rejected, you’ll likely have to file on paper, and both of you will receive an IRS notice asking you to review the rules. If your ex refuses to back down, the case moves to an audit, and the parent who filed the improper claim owes back any tax benefit received plus interest and a penalty of 20% or 75% of the underpayment.
What the IRS Does When Two Parents Claim the Same Child
The IRS matches Social Security numbers as returns come in. Whichever return arrives first is accepted; the second e-filed return is rejected with an error saying the dependent has already been claimed. If that second return is yours, you have two options: remove the child and file without them, or mail a paper return claiming the child anyway. The paper route can delay your refund by months, but it preserves your claim.
Starting with tax year 2024 returns, there’s an exception. If you have a valid Identity Protection PIN for yourself and include it, the IRS will accept your e-filed return even if your child’s SSN was already used on another return.1Taxpayer Advocate Service. Protect Yourself From Tax-Related Identity Theft – Get an Identity Protection PIN Both returns being accepted doesn’t mean both parents get the credits. It just means neither of you is stuck on paper while the dispute plays out.
Once both returns are in the system, the IRS mails a CP87A notice to each parent. The notice explains that someone else claimed the same dependent and asks you to review the rules and amend if you were wrong. It doesn’t identify the other filer.2Internal Revenue Service. Understanding Your CP87A Notice CP87A is informational, not an audit. If you’re confident your claim is correct, you don’t have to send anything in response.3Internal Revenue Service. Notice CP87A – You Need to Make Sure Someone Is Your Dependent If neither of you backs down, the IRS opens an audit to decide who was entitled to the claim, and you’ll then receive a CP75 letter requesting documentation with a deadline, usually 30 days.4Internal Revenue Service. Notice CP75
How the IRS Decides Which Parent Wins
The IRS decides based on where the child slept at night. The parent the child lived with for the greater number of nights during the year is the custodial parent for tax purposes, and that parent has the default right to claim the child.5Internal Revenue Service. Claiming a Child as a Dependent When Parents Are Divorced, Separated or Live Apart For a full calendar year, that means at least 183 nights. If the nights were exactly equal, the tiebreaker goes to the parent with the higher adjusted gross income.
Nights when your child was temporarily away from home still count as time lived with you. School, summer camp, a hospital stay, or a vacation don’t break the residency count as long as your home is the child’s regular residence.6Internal Revenue Service. Qualifying Child Rules
A Divorce Decree Alone Is Not Enough
A common misconception is that a divorce decree saying “Dad can claim the child in even years” settles the question for the IRS. It doesn’t. For any decree or separation agreement that took effect after 2008, the non-custodial parent cannot attach pages from the decree in place of the required IRS release form.7Internal Revenue Service. Form 8332 – Release/Revocation of Release of Claim to Exemption for Child by Custodial Parent Without the signed release, the IRS treats the custodial parent’s claim as the winner regardless of what a family court judge ordered. Enforcement of the decree itself is a matter for state court, not the IRS.
When Your Ex Is Legally Allowed to Claim the Child
The custodial parent can voluntarily release the claim by signing IRS Form 8332. A separate form is required for each child, and the non-custodial parent must attach it to their return every year they use it.7Internal Revenue Service. Form 8332 – Release/Revocation of Release of Claim to Exemption for Child by Custodial Parent If you never signed Form 8332 and your ex isn’t the custodial parent, their claim is improper, whatever the divorce decree says.
If you previously signed Form 8332 and want to take it back, complete Part III of a new Form 8332 and give a copy to your ex. The revocation takes effect no earlier than the tax year after you file it, and you cannot revoke it retroactively for a year that has already passed.7Internal Revenue Service. Form 8332 – Release/Revocation of Release of Claim to Exemption for Child by Custodial Parent
Benefits You Keep Even If You Release the Claim
Signing Form 8332 transfers only certain benefits: the child tax credit, the additional child tax credit, and the credit for other dependents. Several valuable benefits stay with the parent the child lived with and cannot be transferred, no matter what any form or court order says.5Internal Revenue Service. Claiming a Child as a Dependent When Parents Are Divorced, Separated or Live Apart
- Earned Income Tax Credit. The child must have lived with you more than half the year. Form 8332 has no effect on EITC eligibility.6Internal Revenue Service. Qualifying Child Rules
- Dependent care credit. Only the custodial parent can claim childcare costs that allowed them to work.
- Head of household filing status. This requires the child to have lived with you for more than half the year.
If you’re the custodial parent, claim the EITC, the dependent care credit, and head of household status even in a year when your ex properly claims the child tax credit. Many parents assume releasing the dependency hands over everything. It doesn’t.
What to Do Right Now
If your e-filed return was rejected because your ex claimed your child first and you’re entitled to the claim, file a paper return that includes your child. Don’t drop the child from your return just to get through e-file, because that concedes the credits you’re owed. Keep proof of mailing.8Internal Revenue Service. IRS Audits
Start gathering residency documentation now, even before the IRS asks. If the case goes to an audit, you’ll want records showing your child’s address matched yours for more than half the year: school records, medical or dental records, daycare statements, social service records, and a lease or utility bills in your name at that address. School records are the most commonly used proof, but they need to cover more than half the tax year. A single semester’s records may not be enough on their own.9Internal Revenue Service. Topic No. 654 – Understanding Your CP75 or CP75A Notice, Request for Supporting Documentation
Get an IP PIN Before Next Filing Season
If you expect the same fight next year, request an Identity Protection PIN for yourself and your dependents. An IP PIN is a six-digit number the IRS assigns that must be included on any return using your SSN. It lets you e-file even when someone else has already claimed your child, avoiding the paper delay.
Anyone with a Social Security number or ITIN can request an IP PIN through their IRS online account, and parents can request them for their dependents. If you can’t verify your identity online, you can file Form 15227 (available if your AGI is below $84,000 for single filers or $168,000 for joint filers) or visit a Taxpayer Assistance Center in person.10Internal Revenue Service. Get an Identity Protection PIN Dependents under 18 have to use one of the alternative methods rather than the online tool.
Amending a Return to Fix the Claim
If you realize you shouldn’t have claimed the child, file an amended return using Form 1040-X to remove them. If you were entitled to the claim but left the child off to get through e-filing, you can amend to add the child back and pick up the credits. You can e-file an amended return for the current year and the two prior years. Complete Part I (Dependents) on page 2 with all dependents claimed on the corrected return, and add a brief explanation in Part II.11Internal Revenue Service. Instructions for Form 1040-X (Rev. December 2025)
There’s a deadline for claiming a refund on an amended return. You must file within three years of the date you filed the original return or two years from the date you paid the tax, whichever is later.12Internal Revenue Service. Time You Can Claim a Credit or Refund The clock runs from your original filing date, so don’t sit on it.
What Your Ex Faces for an Improper Claim
If the IRS decides your ex was not entitled to the claim, they have to repay whatever tax benefit they received, with interest running from the original due date of the return. On top of repayment, the IRS can add an accuracy-related penalty of 20% of the underpayment where the improper claim resulted from negligence or disregard of the rules.13Office of the Law Revision Counsel. 26 USC 6662 – Imposition of Accuracy-Related Penalty on Underpayments If claiming the child cut your ex’s tax by $2,000, the penalty alone would be $400 on top of returning the $2,000 plus interest.
If the IRS determines the claim was fraudulent rather than careless, the penalty rises to 75% of the underpayment.14Office of the Law Revision Counsel. 26 USC 6663 – Imposition of Fraud Penalty On that same $2,000, the fraud penalty would be $1,500. Once a dependent claim is flagged, the IRS can also audit the rest of the return.
Where the improperly claimed child was also used to grab the Earned Income Tax Credit, the consequences get steeper. The IRS can ban the filer from claiming the EITC for two years if the claim was reckless or intentional, or for ten years if it was fraudulent. The ban applies to all future EITC claims, not just for the child in question.
The 20% accuracy-related penalty can be waived for reasonable cause and good faith. The IRS looks at what effort the filer made to determine the correct treatment, the complexity of the issue, and whether they relied on a qualified tax professional who had the full facts.15Internal Revenue Service. Penalty Relief for Reasonable Cause A parent who genuinely believed they were the custodial parent under a confusing custody arrangement has a stronger case than one who ignored the rules. Reasonable cause is not a defense to the 75% fraud penalty.