Introduction: Most approaches to reducing the socially inappropriate behavior of adolescents target the individual rather than a group. Evidence suggests greater efficiency and longlasting effects may be achieved when groups of peers work together to make meaningful contributions to their communities through service learning projects. In the systems-intervention program presented here, titled "Positive Peer Group", interventions are implemented with the goal of developing enhanced skills, increasing personal responsibility, increasing students' bonding to their school community, developing an ability to manage conflict responsibly, identifying with positive peers, and increasing social skill repertoires. Method: The subjects were 198 students attending 17 schools with matched controls in Ohio, USA. Prior to entry into the program students exhibited characteristics signaling a capacity for leadership whether as positive role models or as potential leaders of a disaffected group likely to engage in negative behavior patterns. Students experiencing the experimental condition were offered opportunities to work together in small, heterogeneous groups on projects that contributed to improving their school or solving a problem that they themselves recognized within their school or community. Results: Self-report measures taken pre- and post-intervention confirm statistically significant improvements in behavioral accountability, bonding to school, anger management, and the establishment of a psychological sense of school membership--all primary goals for this intervention. Discussion and Conclusion: These data strongly support the contention that increased affiliation with the life of the school established through service-learning enhances social skill development and may inoculate children from becoming further disaffected. (Contains 5 figures and 5 tables.)