This article describes what is currently known about the peer relationships of children with attention-deficit/hyperactivity disorder (ADHD). This topic is addressed both from the perspective of how ADHD initially contributes to problematic relationships with peers, and also from the perspective of how peers' reactions to these problems may serve to maintain them. Given the limited improvement typically obtained in treatment studies that use peer report measures as outcomes with ADHD samples and the well-documented predictive validity of peer reports for later adjustment, the need for more intensive interventions and novel approaches to address the peer problems of children with ADHD is emphasized.