Given the importance of the therapeutic alliance in achieving positive treatment outcomes, research is needed to illuminate the factors that contribute to the development of this important relationship. The aim of the current study was to expand upon the existing literature by examining predictors of the early therapeutic alliance among adolescents treated in two outpatient programs. Use of multilevel modeling techniques revealed that the majority of the variance in adolescents' ratings of the therapeutic alliance was due to adolescent factors (91%), while the variance in therapist ratings of alliance were nearly equally divided between adolescent and therapist factors (52% vs. 48%). Participant age was found to be the only significant predictor of therapist-rated alliance, with therapists reporting higher alliances with older adolescents. Adolescents reporting higher levels of social support, greater problem recognition, and more reasons for quitting also reported higher therapeutic alliance ratings. Future research is needed to examine if early identification of adolescents with low social support and problem recognition combined with brief treatment readiness interventions can be a promising approach to help improve therapeutic engagement and post-treatment substance use outcomes.