This study analyzed measures aggregated at the school level to identify key predictors of drinking alcohol, binge drinking, smoking cigarettes, and using marijuana. Using data collected from 6th through 12th grade students between 2011 and 2015, we identify school-level variables that predict school-level prevalence in the subsequent year. Data included prior year assessments of: (1) school-wide prevalence, (2) perceived ease of access to drugs, (3) perceived adult disapproval of drug use, (4) perceived peer disapproval of drug use, and (5) perceived prevalence of drug use. We regressed grade-level behaviors on predictor variables from the previous school year. In middle schools, prior grade prevalence and prior grade perceived norms were significant predictors of subsequent grade prevalence. For high schools, prior year prevalence, aggregated peer norms, and perceived ease of access predicted subsequent use. These analyses provide evidence that a school’s culture is predictive of changes in prevalence over time.