A special issue on adolescent mental health is presented. Articles discuss promotion of positive youth development in schools, the importance of teacher–student relationships for adolescents with high-incidence disabilities, adolescents' moral engagement in urban settings, research on highly stressful environments that foster aggressive behavior in children and adolescents, research on risk factors linked to adolescent mothers' mental health, peer victimization and mental health in early adolescence, research on ethnic and racial identity and adolescent well-being, links between sports involvement and science success for high-school women, and promotion of student resilience in school contexts.