This study examines whether positively biased self-perceptions relate to social behaviors in children with attention-deficit/hyperactivity disorder (ADHD) as compared to control children. The social behaviors of children with ADHD (n = 87) were examined relative to control children (CTL; n = 38) during a laboratory-based dyadic social interaction task. Children with ADHD were subgrouped into those with a positive illusory bias (PIB) in their self-perceptions (ADHD + PIB) versus those without such a bias (ADHD - PIB). Using a behavioral coding system adapted for this study, ADHD + PIB, ADHD - PIB, and CTL participants were compared on objectively coded social behaviors occurring within the context of the social interaction task. Whereas both ADHD groups displayed more disruptive behavior than controls, only the ADHD + PIB group displayed less prosocial behavior and less effortful behavior. This study breaks new ground by examining positively biased self-perceptions as they relate to social behavior in children with ADHD and provides promising new insight into the social problems experienced by these children. (Contains 3 tables and 1 figure.)