Policy and practice governing the payment of child support after parental separation assumes as a general principle that a child is dependent until age 18. By contrast, government income support policy assumes that children are dependent until age 25 if they are studying full time. This inconsistency creates 'fuzzy' boundaries around income support for young adults who have not yet attained financial independence. What does this mean for children whose parents have divorced? This article considers this question, drawing on data from the Institute's Australian Divorce Transitions Project. A unique characteristic of the project is that information about child support was recorded for children 18 years or over, as well as for those under 18 years. Discussion includes the legislative framework, parents' awareness of eligibility, and parents' and children's views on financial support. The central finding of the paper is that children aged 18 years or over who are eligible to receive child support rarely do so.