Attention-deficit/hyperactivity disorder (ADHD) is associated with functional impairments in different areas of daily life. One such area is social functioning. The purpose of this paper is to critically review research on social dysfunctioning in children with ADHD. Children with ADHD often have conflicts with adults and peers, and suffer from unpopularity, rejection by peers, and a lack of friendships, in part as a consequence of their ADHD symptoms. Comorbid oppositional defiant or conduct disorder aggravates these impairments. In some cases the inadequate social behavior of children with ADHD may be phenomenologically and etiologically related to pervasive developmental disorders (PDD). However, the causes and consequences of PDD symptoms in ADHD are understudied. Also, the relative contributions of ADHD, on the one hand, and comorbid disorders, on the other, to the course of social impairments are unknown. Social dysfunctioning in children with ADHD appears to increase their risk of later psychopathology other than ADHD. Thus far effective treatment for social dysfunctioning is lacking. Future research should address the exact nature and long-term consequences of social dysfunctioning in children with ADHD, and focus on development of effective treatment strategies.