Major depression in adolescents is common but often untreated, underscoring the need for effective prevention. Several prevention programs have been developed, with cognitive-behavioral (CB) interventions having the largest evidence base. Meta-analyses reports find small magnitude effects for depressive symptom reductions at post-intervention and follow-up, with larger effects for selective/indicated than universal programs. More encouraging, long-term studies suggest that depressive disorder rates are approximately 40% lower for CB programs compared to controls. Needed research includes improving the existing programs that work well, developing a more sophisticated understanding of why CB prevention works, identifying subgroups who most benefit from CB, continuing the transition to effectiveness research, developing effective depression prevention programs for college-aged young people, and a broader evaluation of CB-based computerized prevention efforts.