text: i pay child support to my ex girl friend for our daughter legally can i claim her on my taxes?   only one person may claim a child as a deduction, and only the parent who provides 51% or more of the child's support can claim him/her. the exception is if the custodial parent allows you to claim them by signing form 8332. the top source below is a guide for non-custodial parents and the second one is form 8332.