Can my sons mom let her boyfriend claim my son on his taxes? I pay child support, but there is nothing in the court documents that states who can claim our son on taxes.

[Opus 17 · Accepted solution]

The only parent who has the automatic right to claim a child as a dependent is the parent where the child lives more than half the nights of the year (they do not have to be consecutive).  Payment of child support is not a determining factor.

Assuming that is your ex, then she is the only parent who can claim the child as a dependent. If she is a taxpayer for 2018 (has income more than $12,000, or has lower income but files in order to claim any deductions or credits) then she must claim the child and she can't allow her boyfriend to claim the child even if she wants to. 

If she is not a taxpayer for 2018, then either you or the boyfriend might be able to claim the child as an "other dependent".  This would go to whomever provided more than half the child's total financial support for 2018.  Your child support counts in your favor, but if the boyfriend provides a place to live, he gets to count 1/3 of his rent or the rental value of his home, as support for the child, plus 1/3 the utilities, 1/3 the household food, and so on.  

However, the child must also live with the boyfriend for the entire calendar year.  If the child lives with you part of the year, then the boyfriend can't claim the child, but if you don't provide more than half the child's support, then you can't claim the child either.  In that case, everyone who provides more than 10% of the child's support must sign a "multiple support agreement" that specifies which person gets to claim the child.  If no MSA, then no one can claim the child as a dependent.

A child who does not live with you can be claimed by you as a dependent for the child tax credit only if the other parent gives you a signed form 8332.  Even with that form, a child that does not live with you never qualifies you for EIC or to file as head of household.

[AlanT]

Only if the following requirements are met.  The "person" below for your situation would be your child.  "You" would be the boyfriend. 

To be a Qualifying Relative -

1. The person cannot be your qualifying child or the qualifying child of any other taxpayer. A child is not the qualifying child of any other taxpayer if the child's parent (or any other person for whom the child is defined as a qualifying child) is not required to file an income tax return or files an income tax return only to get a refund on income tax withheld.

2. The person either (a) must be related to you or (b) must live with you all year as a member of your household. 

3. The person's gross income for the year must be less than $4,150 (social security does not count) in 2018

4. You must provide more than half of the person's total support for the year.

5. The person must be a U.S. citizen or a U.S., Canada, or Mexico resident for some part of the year.

6. The person must not file a joint return with their spouse.

[Opus 17]

This answer is from the boyfriend's perspective.   This is what the boyfriend must be able to prove in order to claim the child.

[AlanT]

Thanks, I amended to give clarification.