The impact of group treatment programs on the social skills and peer relations of psychiatrically hospitalized children with disruptive behavior disorders was evaluated. Children assigned to a social-cognitive skills training group (SCST; n = 36) were matched to children who participated in a social activity group (SA; n = 20). The results indicated significantly greater pre-post improvements for the SCST than the SA group in child-reported loneliness, staff sociometric ratings, role-play performances, and in vivo behavioral observations of individual social skills. Child diagnoses did not differentially effect treatment outcomes. The findings are discussed in the context of training, clinical, and methodological issues.