We examined psychological functioning in siblings of children with Attention Deficit Hyperactivity Disorder (ADHD). Siblings of children diagnosed with ADHD (n = 45) between the ages of 9 and 13 and a control group (n = 46) within the same age range composed of siblings of children with no diagnosed disorders completed measures of psychological functioning. A significant multivariate difference was observed on these measures across groups. Post hoc investigation of the univariate means revealed one significant group difference, which occurred on a measure of Trait Anger. This finding suggests that future research on family members of children with ADHD may be warranted.