This study examined how cultural adaptation and delivery quality of the school-based intervention keepin' it REAL (kiR) influenced adolescent substance use. A total of 39 middle schools in rural communities of two states in the U.S. were randomly assigned to one of three conditions (i.e., control, urban non-adapted kiR, and rural adapted kiR). Data were adolescent self-reported lifetime substance use and trained observers' ratings of delivery quality from the video records. Observer ratings

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... re-coded into high and low quality to create four comparison groups (i.e., low/high delivery quality in urban kiR condition and low/high quality in rural kiR condition). Controlling for substance use report in 7 th grade, findings compared 9 th graders' (N = 2,781) lifetime alcohol, cigarette, marijuana, and chewing tobacco use. Mixed model analyses revealed that rural youth receiving the adapted rural curriculum reported significantly less cigarette use than rural youth in the control condition. Those in mismatched intervention (non-adopted urban condition) did not significantly differ from the control participants, but a significant difference was observed based on the delivery quality. Rural youth in the high-quality urban condition reported less marijuana use than rural youth in the lowquality urban condition. Research implications and future directions are discussed.