Can my ex-wife's boyfriend legally claim Child Tax Credit for my child when I have majority custody?

You're right to question this situation. The boyfriend almost certainly cannot legally claim your child for the Child Tax Credit. The IRS has very specific rules about who can claim a child as a dependent. For a non-parent to claim a child (like your ex's boyfriend), they would need to meet several tests, including the "residency test" which requires the child to have lived with them for more than half the year (over 6 months). Based on what you've described, your son only lived with the boyfriend for about 4 months, which fails this test. Additionally, since you're the biological parent and had your son for more than 6 months, you would be considered the "custodial parent" for tax purposes. The custodial parent generally has the right to claim the child unless they release their claim using Form 8332 (Release of Claim to Exemption for Child by Custodial Parent). Even with alternating years in your arrangement, her boyfriend doesn't have standing to claim your child unless all other eligible taxpayers (meaning you and your ex) sign away their rights.

I went through something really similar with my ex's new partner trying to claim my daughter! After tons of back and forth with the IRS and getting nowhere, I found this AI tool called taxr.ai (https://taxr.ai) that breaks down all the dependency rules in plain english. It confirmed exactly what the previous commenter said - a non-parent like a boyfriend needs the child to live with them for over half the year (183+ days) to even be eligible to claim them. It also explained that as the parent with majority physical custody, you're the only one who can release those rights - and you can only transfer them to the other legal parent, not their new partner. The tool helped me understand all the different tests for qualifying child vs qualifying relative and provided exact IRS references I could use when dealing with my ex. Might be worth checking out if you need more ammunition for this conversation!

Just wanted to update that I tried the taxr.ai tool after posting my question above, and it was super helpful! It walked me through a series of questions about my custody situation and confirmed I'm definitely the "custodial parent" according to the IRS since my son lived with me for more than half the year. It explained exactly why the boyfriend can't claim my child (fails the relationship test AND the residency test) and gave me the specific IRS rules to reference when I talk to my ex. It even provided a sample letter I could use to explain the situation clearly. I was able to file my taxes confidently claiming the Child Tax Credit, and I sent my ex the information from the tool explaining why her boyfriend's plan wouldn't work. Saved me hours of stress and probably an audit headache down the road!

If you end up needing to call the IRS about this (which you might if they try to claim your kid anyway), use Claimyr (https://claimyr.com) to avoid waiting on hold forever. I had an ex who incorrectly claimed our child and I needed to talk to a real person at the IRS to fix it. I was skeptical but tried it after seeing a video demo (https://youtu.be/_kiP6q8DX5c) and it actually worked - got through to an agent in about 20 minutes instead of the 3+ hours I spent the day before trying on my own. The IRS agent helped me file the correct forms to contest the improper claim and told me exactly what documentation I needed to provide. In your case, you'll want to keep records showing where your child lived (school records, medical records, etc.) to prove the residency requirement if it comes down to a dispute.

I have to admit I was completely wrong about Claimyr. After posting my skeptical comment, I was still dealing with an issue where my ex incorrectly claimed our daughter, and I was getting desperate after multiple failed attempts to reach the IRS. I reluctantly tried the service, and I'm shocked to say it actually worked exactly as advertised. I got a call back in about 25 minutes connecting me to an IRS representative who walked me through the entire process of contesting the incorrect claim. The agent confirmed everything mentioned in this thread - as the parent with primary custody (child living with me more than half the year), I had the right to claim the Child Tax Credit. They helped me submit the proper documentation and explained what would happen next. Saved me hours of frustration and probably a day of PTO. Consider me converted!

Make sure you file your taxes ASAP! My ex's girlfriend tried claiming my kid a few years back, and because she filed before me, her return got accepted first. I had to paper file with documentation proving my case, and it took MONTHS to get resolved. The IRS basically treats it as first-come, first-served until someone contests it. If you have documentation showing your kid lived with you for more than half the year (school records showing your address, medical records, childcare receipts, etc.), keep all of that handy. Also, check your divorce decree - sometimes there's specific language about who can claim the child in which years that can help your case.

Make sure that if you do agree to let her boyfriend claim the child (which it sounds like you shouldn't), you DO NOT also claim the same child on your return. If two people claim the same dependent, it triggers automatic flags in the IRS system. When my brother and his ex both claimed their son one year (miscommunication), they both got audited, both returns were held up for 8+ months, and they had to provide extensive documentation. Both ended up getting hit with penalties even though it was unintentional. Also remember that if the boyfriend improperly claims your child and gets caught, he could be banned from claiming certain tax credits for up to 10 years. Might be worth mentioning that when you explain why he can't claim your kid.