Knowledge of the clinical course in treated adolescents is fundamental to determining the influence of treatment on long-term functioning and the factors associated with change in the severity of alcohol problems over time. This symposium, held at the 2002 annual Research Society on Alcoholism meeting and organized by Tammy Chung and Christopher S. Martin, presented research on the course of alcohol-related problems in treated adolescents who were followed prospectively for 1 to 8 years. Presentations included (1) Alcohol use outcomes at 1 year among adolescents in the drug abuse treatment outcomes studies (DATOS-A), by Christine E. Grella; (2) Pathways and predictors of the course of adolescent alcohol problems across 1- and 3-year follow-ups, by Tammy Chung; (3) Young adult outcomes of an adolescent clinical sample at 5-year follow-up, by Ken C. Winters; and (4) Trajectories of alcohol involvement following addiction treatment through 8-year follow-up in adolescents, by Ana M. Abrantes, Denis M. McCarthy, Gregory A. Aarons, and Sandra A. Brown. Sandra A. Brown, discussant, commented on the presentations. Results from these studies indicate multiple pathways of change, distinguished by fluctuations in the chronicity and severity of alcohol problems. Across studies, most adolescents showed reductions in alcohol use and problems after treatment, with concurrent improvements in psychosocial functioning. Findings highlight the influence of other drug use on posttreatment patterns of alcohol involvement and the need to consider the effect of normative developmental transitions on the course of adolescent-onset substance use disorders.