Alcohol abuse and dependence are among the most common psychiatric disorders occurring in adolescents. This article will examine clinically relevant research on the development, diagnosis, course, treatment, and adult outcomes of adolescent alcohol use disorders (AUDs). A developmental history of childhood mental disorders reflecting psychological dysregulation predicts adolescent AUDs. The DSM-IV AUD definitions developed for adults are generally valid for adolescents, although some adolescents with significant alcohol problems are not identified by this diagnostic system. Adolescents with AUDs typically have other substance involvements, comorbid mental disorders, and problematic family relationships. While biomedical complications seen in chronic alcoholic adults are typically absent, acute biomedical complications of intoxication, such as alcohol poisoning or traumatic injury, may contribute to excess mortality in adolescents. Psychosocial interventions promoting abstinence are the most common treatments for AUDs, with credible empirical support available for family-based approaches. While few drug trials have been completed for adolescents with AUDs, pharmacological interventions are available for alcohol withdrawal, craving, and comorbid mental disorders. Some adolescents with AUDs manifest chronic alcoholism in adulthood; many others transition to abstinence or normative drinking. Alcohol abstinence is the primary treatment focus, although other complications need to be addressed and treated to foster optimal clinical outcomes.