Core areas of the adolescent delinquency issue include epidemiology, correlates and associated features, recidivism, and treatment. Multiple perspectives on adolescent delinquency are reflected in research on personality and cognitive features, family and peer relations, and school functioning. Special research topics focus on delinquency in females, sexual and violent offenders, and a typology of delinquency. Promising treatment options encompass individual, family, peer, and institutional therapy. The empirical findings show that delinquent behavior is associated with the characteristics of individual adolescents and the systems in which they grow and develop. These systems include the family, peers, school, and neighborhood. It is concluded that suprisingly few consistent findings have emerged from research on correlates of delinquent behavior and that the further study of developmental processes and systemic contexts will advance current understanding of delinquent behavior in adolescents. It is also concluded that chronic delinquent behavior can be treated effectively. Such treatment should be intense, intervene in the natural systems in which adolescents are involved, be capable of addressing multiple determinants of delinquent behavior, and be conducted by skilled therapists. 404 references, 3 figures.