The primary goals of the proposed study are: (a) to determine whether children's peer relations (i.e., peer acceptance, peer rejection) and friendship support predict psychological functioning (internalizing and externalizing problems) in adolescence; (b) to evaluate whether peer friendship support is a significant factor that moderates the linkage between children's peer relations and their adjustment during adolescence; (c) to extend the assessment of adolescent emotional adjustment to include subjective distress (loneliness, social anxiety, low self-esteem) and quality of friendships/social experiences, and to evaluate these variables as potential mediators between children's peer relations, friendship support and the primary outcomes (internalizing and externalizing problems). A conceptual model is described that summarizes the main study goals and provides a framework for the proposed investigation. Secondary aims of this project are: (a) to extend the proposed conceptual model to our understanding of children's academic progress over the time period from middle childhood to adolescence, and (b) to develop operational criteria for identifying children "at risk" for future adjustment difficulties. The proposed study builds upon an existing data base. This is a five-year, prospective, follow-up investigation of a large cohort of children (N = 515) who were previously tested on peer acceptance, peer rejection, peer support, behavior problems and academic achievement during the late elementary school grades (4th through 6th). These children will be re-evaluated five years later, during adolescence. All adolescents will complete measures of behavioral adjustment, subjective distress, friendship quality, and friendship support. Parents will also provide information on the adolescents' adjustment. Measures of academic achievement will be gathered from school records. Peer ratings of acceptance and rejection will also be obtained for a subset of the follow-up cohort (38%). Peer ratings will be conducted as part of a school-approved project; this peer rating data will be available from the adolescents' school records. Primary analyses will focus on the ability of early peer relations and peer friendship support to predict adolescent adjustment outcomes. The data from the proposed investigation will provide important information regarding the role of peer relations and social support in children's adjustment, as well as the specific mechanisms that underlie such relationships. Furthermore, it permits an evaluation of how these processes differ for boys and girls. Such findings will significantly enhance our ability to identify children who are "at risk" for future maladjustment, and to design and implement appropriate preventive mental health interventions for "at risk" youth.