Can my wife's ex-husband claim our stepdaughter as a dependent after she turns 18?

Full question:

I have a step-daughter that turns 18 in July, and will be attending college as a full time student. My wife's divorce decree notes that child support ends when the child reaches 18. In the provisions of the decree, the parents agreed to claim their daughter as a dependent every other year. My wife is the custodial parent. My question is: if my stepdaughter continues to spend a majority of her free time at my residence, and we provide 1/2 the financial support for her education, as well as a home when she comes home from college, would my wife's ex-husband have any right to claim his daughter as a dependent at tax time, or would the household providing her more support be eligible to claim her, since she would no longer be a minor child, and the divorce decree would be exhausted? Is the divorce decree exhausted when the minor child turns 18?

• Category: Divorce
• Subcategory: Child Support
• Date: 04/07/2025
• State: Wisconsin

Answer:

In some states, courts can order support beyond the age of 18, known as post-majority support. If a court decides it's appropriate for parents to contribute to a child's college education, it may modify existing child support orders to include education expenses. In Wisconsin, for example, a judge can require support for higher education after high school.

To claim a child as a dependent for federal tax purposes, the child must be under age nineteen at the end of the year or a full-time student under age twenty-four. If the child support order is modified to include post-majority support, it may also specify which parent can claim the child as a dependent for tax purposes. According to Wisconsin law, the court must determine which parent is eligible to claim the child based on various factors, including financial support and health care responsibilities (Wis. Stat. § 767.511).