Question: Are child support payments deductible by the payer or can the payer claim an exemption for the child?

Answer: Child support payments are neither deductible by the payer nor taxable income to the payee.
The payer of child support may be able to claim the child as a dependent.

The parent with whom the child lived for the greater part of the year is the custodial parent for income tax purposes.

Generally, the child is the qualifying child of the custodial parent, and the custodial parent is allowed an exemption for the child if the other dependency tests are met.

The noncustodial parent may claim an exemption for the child if the custodial parent signs a Form 8332 (PDF), Release/Revocation of Release of Claim to Exemption for Child by Custodial Parent, or a substantially similar statement, and the noncustodial parent attaches it to his or her return.