RESEARCH and clinical work with hyperactive children have focused on problems with attention, self-control, disciplinary problems, and school achievement. Remarkably little emphasis has been placed on the social functioning of these youngsters or the difficulties which may follow from problems with peers. Indeed, relatively little empirical data exist on the social competence or incompetence of hyperactive children with agemates or siblings, although the importance of peer interaction to general adjustment is accepted virtually without question.Recently there has been renewed interest in social behaviour, social cognition, and patterns of peer interaction in non-clinical populations of children (e.g. Asher, Oden and Gottman, 1976;Hartup, 1970;Shantz, 1975) and there is wide agreement that satisfactory relations with peers are a crucial facet of normal development. Evidence from several studies indicates that popularity with peers is an important predictor of adjustment in childhood and adulthood. Cowen et al. (1973) reported that children who were rated negatively by peers in third grade were more likely to end up on the psychiatric register in early adulthood. Indeed, peer ratings were more accurate predictors of later adjustment than teacher or parent reports of school achievement. The long-term follow-up studies of Robins (1966) and Roff (1961) likewise indicate that poor peer relations are likely precursors of adult psychopathology, while Garmezy (1975) notes that children at risk are similarly characterized by problems with peers. Subjects in many of these studies include heterogeneous groups of aggressive and withdrawn children, many of whom are very likely to have been hyperactive.As Hartup (1976) has argued in his discussion of peer interaction in normal children, socialization within the peer group is an important part of development. He suggests that socialization of aggression, morality, and sex-typing, for example, are very strongly influenced by peer group experiences. Moreover, positive peer relations are associated with social competence, school achievement, and general adjustment. Given the strong link between social success in the peer group and other indices of adjustment and maladjustment across the age range from the preschool years (Kohn, 1976;Bronson, 1966) through adulthood (Robins, 1966;Roff, 1961), it appears obvious that some consideration should be given to peer interaction in children specifically diagnosed as hyperactive.•Requests for reprints to: