Substantial numbers of children and adolescents experience symptoms of sadness, dysphoria, and other characteristics associated with depression. The nature of depression in children and adolescents has presented challenges in identification and definition. This chapter reviews research on depression in children and adolescents. Three current conceptualizations of depression are presented: depressed mood, depressive syndrome, and major depressive disorder. The chapter notes that the consequences of depression are quite serious and can include social impairment and adolescent depression and suicide. Studies indicate several risk factors for depression in childhood and adolescence, including: (1) individual factors including biological, cognitive, and social problem-solving and coping skills; and (2) contextual factors including social context, family, and stress. The chapter examines prior studies of preventive interventions aimed at depressive symptoms and disorder in young people in three categories: (1) universal preventive intervention; (2) selective preventive intervention; and (3) indicated preventive intervention. The chapter uses this research as a basis for setting future directions for the development of programs to prevent depression during childhood and adolescence; these directions include: (1) reducing suicide among youth by recognizing depression as a risk factor; (2) reducing mental disorder among youth, including addressing depression; and (3) enhancing quality of life for overall health improvement. (Contains 125 references.) (SD)