Can the noncustodial parent claim an exemption for his or her child support?

In general, when a couple do not or cannot file a joint return, the determination of which of them can claim the dependency exemption is made based on a consideration of which parent has custody, who supports the child and the degree of cooperation between the parents.

The I.R.S. is not concerned about which parent claims the exemption, only that the exemption is not claimed by both parents.

In general, the custodial parent is the one who can take the dependency exemption. For the purposes of the I.R.S, the "custodial parent" is the parent with whom the child or children live for more than six months of the year, no matter what the divorce decree may say.