Objective. Emerging research indicates that overweight children with social impairments are less responsive to weight control interventions over the long term. A better understanding of the breadth and psychosocial correlates of social problems among overweight youth is needed to optimize long-term weight outcomes. Methods. A total of 201 overweight children, aged 7–12 years, participated in a randomized controlled trial of two weight maintenance interventions following family-based behavioral weight loss treatment. Children with HIGH ( T≥65) versus LOW ( T<65) scores on the Child Behavior Checklist Social Problems subscale were compared on their own and their parents’ pre-treatment levels of psychosocial impairment using multivariate analysis of variance. Hierarchical regression was used to identify parent and child predictors of social problems in the overall sample. Results. HIGH ( n=71) children evidenced greater eating disorder psychopathology and lower self-worth, as well as a range of interpersonal difficulties, compared with LOW children ( n=130; ps<0.05). Compared with parents of LOW children, parents of HIGH children reported greater levels of their own general psychopathology ( p<0.05). Parent psychopathology significantly added to the prediction of social problems in the full sample beyond child sex and z-BMI ( ps<0.01). Conclusion. A substantial minority of overweight youth experience deficits across the social domain, and such deficits appear to be associated with impairment in a broad range of other psychosocial domains. Augmenting weight loss interventions with specialized treatment components to address child and parent psychosocial problems could enhance socially-impaired children’s long-term weight outcomes and decrease risk for later development of psychiatric disturbances. [ABSTRACT FROM AUTHOR]