Nationally, approximately 10% of adolescents in need of treatment for a substance use (SU) disorder receive treatment. School-based treatment may provide an important opportunity to reduce the treatment gap by facilitating access to services. While some school-based SU treatment exists, little is known about whether newer, evidence-based treatments (e.g. Adolescent Community Reinforcement Approach [A-CRA]) can be well implemented in schools. The objectives of this study were to compare adolescents receiving A-CRA services in school-based versus clinic-based settings in regard to (1) intake characteristics, (2) treatment implementation quality, and (3) clinical outcomes. Results suggest that A-CRA in school-based settings was more likely to reach girls and youth with shorter SU histories; A-CRA was well implemented within school-based settings and the school-based group had equivalent or better outcomes than the clinic-based group.