The prevalence of overweight in children and adolescents has increased significantly during the last two decades. While there are empirically supported weight management interventions for school age children, treatment findings with overweight adolescents are not as consistent. A potential limitation of weight control interventions for adolescents is the minimal attention given to the peer group as an active component of treatment. We have promising findings from a pilot study that involves adding an innovative peer-based intervention (peer-based skills training; PBST) to cognitive- behavioral weight management treatment for adolescents. The purpose of the proposed study is to expand the pilot by: 1) increasing our sample size, 2) assessing weight loss over a longer time period, and 3) evaluating the role of psychosocial variables, as well as physical activity and diet, in mediating treatment outcome. It is hypothesized that overweight adolescents randomized to cognitive-behavioral treatment with peer enhancement will demonstrate greater weight loss at long term follow-up than adolescents randomized to cognitive-behavioral treatment with exercise.