Suicide is an issue of increasing concern for professionals who work with adolescents and their families. Over the past three decades, the rate of suicide has increased dramatically among 15- to 24-year-olds and is the third leading cause of death in this age group. Previous theoretical approaches to understanding adolescent suicide (i.e., Durkheim's sociological theory of suicide, social learning theory, psychological theory, and family systems theory) are reviewed, and the utilization of human ecological theory is proposed. Factors associated with adolescent suicide at the organism (individual), microsystem, mesosystem, exosystem, and macrosystem levels are examined. Finally, examples of prevention and intervention at each level are presented.