This investigation examined personal and environmental predictors of substance treatment outcomes in youth. A 424 adolescents (M=15.9 years, S.D.=1.3) completed comprehensive assessments, including substance use, environmental factors (e.g., family history, social supports), and person-centered variables (e.g., Axis I diagnosis, motivation, self-esteem), at study intake and throughout the year following inpatient treatment. Youth treatment outcomes were assessed by relapse status (abstaining, minor relapse, major relapse) and DSM-IV dependence symptoms at 1 year. Relapse status was predicted by demographic (age), environmental (social supports), and person-centered factors (diagnosis) while dependence symptoms were best predicted by substance use variables alone. Consideration of the general and specific nature of risk and protection within the adolescent developmental context were explored.