Child support payments are not tax deductible by the payer and are not taxable income to the recipient. Paying child support does not necessarily entitle you to claim the child as a dependent for tax purposes (a dependency exemption). The Internal Revenue Service (IRS) rules dictate that the parent with whom the child spent the most nights during the tax year has the right to claim the child as a dependent. And if the child spends an equal number of nights with each parent during the tax year, the parent with the higher adjusted gross income (AGI) has the right to claim the child as a dependent. Sometimes the child custody court will order the parents to alternate years of claiming the child as a dependent.

In Washington state, as in the rest of the United States, child support payments are not tax deductible for the payer and do not constitute taxable income for the recipient. This is in accordance with federal tax laws. The right to claim a child as a dependent for tax purposes is generally based on the IRS rules, which state that the custodial parent—the one with whom the child spends the majority of nights during the tax year—has the right to claim the child as a dependent. In cases where the child spends an equal number of nights with each parent, the IRS stipulates that the parent with the higher adjusted gross income (AGI) is entitled to the dependency exemption. It is also possible for a state child custody court to order parents to alternate the years in which they claim the child as a dependent. However, such an order must align with IRS regulations, and the non-custodial parent must typically file IRS Form 8332 if they are to claim the child in a given year.