Problematic peer relations, particularly when chronic, can have a tremendous impact on children's functioning and mental health. Interpersonal aggression is a substantial peer problem among our youth. A history of aggressive behavior with peers is associated with a myriad of later negative outcomes, including delinquency and criminality. Intervention research supports the use of social skills training for decreasing aggression and antisocial behavior problems in aggressive youth as well as for improving their peer relations and social behavior. The goal of this Phase II project is to continue the research and development (R&D) of a group social skills intervention for aggressive adolescents entitled Project Forward (PF). PF builds on an established social skills intervention [Social Skills Group Intervention (S.S.GRIN)] for younger ages (5-12 year-olds) that has shown particular benefits for aggressive children. PF not only extends S.S.GRIN to older children, but also incorporates innovative treatment strategies (video, web based materials) so that PF offers professionals a significant advancement over what is currently available for use with aggressive adolescents. During Phase I, the prototype of the Project Forward product was developed. Two developmental versions of PF were created, i.e., Middle and High school. Each version includes a Facilitator's Manual, 12 session scripts, and accompanying youth and parent handouts. Unique treatment strategies of reality-based video segments for in-group demonstration and web-based homework completion were also integrated into the curriculum. These initial versions were tested for feasibility with community agency professionals (n=14) and school counselors (n=30). Feasibility of the product was successfully established. The Phase I results provide ample support for continued development as well as essential constructive feedback to inform the direction of that development. The proposed Phase II project will utilize the Phase I findings to revise, modify, and extend the PF components in order to maximize quality. Spanish translations of the final versions will be created. A Phase II scientific evaluation of the efficacy of the intervention will be conducted, assessing impact on (1) mastery of social skills and social concepts and (2) changes in social and behavioral functioning. In an experimental design, 36 adolescents in middle school (ages 13 to 15) and 36 adolescents in high school (ages 16 to 18) will be randomly assigned to either a treatment or wait-list control condition (n=18 for each condition for each age group). Professionals will lead the group intervention within a community setting. Outcome data will be collected from parents, teachers, group leaders, as well as the adolescent participants. Parent and adolescent evaluations of the PF product will also be gathered. This research will be instrumental in establishing the PF product as an efficacious competitor in the intervention marketplace.