Can I claim my non-bio son on my taxes?

My son is 8 years old, I am not his bio-dad but have been in his life since before he was born. His mother and I split up around the time he was 2, but I have stayed in his life as his dad ever since. I have never asked to claim him on taxes before, but this year has been hard and he has lived with me full-time since around February of 2024 (at his mom’s house on weekends).

His mother is saying I cannot claim him because I am not related to him, and I don’t know if that is true or not. I really need the tax break. Any insight?

Were you married to his Mom? Assuming not, he is not your qualifying child. If he is anyone else’s qualifying child, you cannot claim him. If he is NOT anyone else’s qualifying child and he lived with you all year long and you provided more than 50% of his support, you may be able to claim him as an other dependent. Since you state that he didn’t start to live with you full time until February, it doesn’t really sound like you can claim him for 2024. But of course, you really didn’t mention all of the relevant information.

@Jules
But going by this logic, I can claim him for 2025?

@Jules
No, we were not married, but he’s been with me 11/12 months. What other relevant information have I left out?

Oren said:
@Jules
No, we were not married, but he’s been with me 11/12 months. What other relevant information have I left out?

You cannot claim a child that is not your biological child as your child. You would be able to claim them as an other dependent, which is a $500 tax credit.

Would make no sense for you to claim the kid as the mother would get $2,000 from the child tax credit. Have her claim the kid and give you $500. lol

@Dara
This is not correct. OP can’t claim the child as a qualifying relative since the child didn’t live with OP all year (as an unrelated person). The mother can’t claim the child either since the child didn’t live with her (or his bio-father) over half of the year. Neither of the adults in question is going to be eligible for any credits for the child.

@Dara
So she could have no contact with him for a whole year and still claim him, and I would have no recourse?

Oren said:
@Dara
So she could have no contact with him for a whole year and still claim him, and I would have no recourse?

No, since the child didn’t live with his mother (or bio-father) over half of the year, she wouldn’t be able to claim the child as a dependent either. The child isn’t going to be eligible to be claimed by either of you as a dependent.

Short version: No, you can’t claim him.

Long version: It’s a bit more involved than you or his mom are saying.

If you were never married to his mother, and you never formally adopted him or had him legally placed with you for foster care or adoption, then legally and for tax purposes, he is not your son. So, he is not your Qualifying Child (one of the two types of dependent).

If he stayed with you for every night of the year (apart from temporary absences like summer camp or hospital stays), then you could probably have claimed him for the $500 other dependent credit. But he didn’t live with you in January, and for the rest of the year he still stayed with his mom on weekends. So, he also is not your Qualifying Relative (the other kind of dependent), and you cannot claim him as a dependent for 2024.

Note that his mom also can’t claim him in 2024 because he didn’t live with her for more than half the year; in this circumstance, it looks like no one is eligible to claim him as a dependent. (Not that I expect that will stop her from saying he lived with her and claiming him anyway, but that doesn’t actually affect you since you can’t claim him either.)

Did you legally adopt him or was there a court-ordered placement with you? If not, you can’t claim him as a qualifying child because you don’t meet the relationship test.

His mother is correct. A non-related person can only be claimed as your dependent if they lived with you all year.