This review synthesized findings from 17 studies since 1998 regarding evaluation of outpatient treatments for adolescent substance abuse. These studies represented systematic design advances in adolescent clinical trial science. The research examined 46 different intervention conditions with a total sample of 2,307 adolescents. The sample included 7 individual cognitive behavior therapy (CBT) replications (n = 367), 13 group CBT replications (n = 771), 17 family therapy replications (n = 850) and 9 minimal treatment control conditions (n = 319). The total sample was composed of approximately 75% males, and the ethnic/racial distribution was approximately 45% White, 25% Hispanic, 25% African American, and 5% other groups. Meta-analysis was used to evaluate within-group effect sizes as well as differences between active treatment conditions and the minimal treatment control conditions. Methodological rigor of studies was classified using Nathan and Gorman (2002) criteria, and treatments were classified using criteria for "well-established" and "probably efficacious" interventions based on Chambless et al. (1996). Three treatment approaches, multidimensional family therapy, functional family therapy, and group CBT emerged as well-established models for substance abuse treatment. However, a number of other models are probably efficacious, and none of the treatment approaches appeared to be clearly superior to any others in terms of treatment effectiveness for adolescent substance abuse. (Contains 2 tables, 1 figure, and 1 footnote.)