Social environment risk factors present in schools and communities have not been thoroughly investigated. This study cross-sectionally examined the social environments of schools and communities, and their influence on adolescent alcohol and drug use. Survey responses of eighth grade students (N = 2309), a random half of their parents (n = 943), community leaders (n = 118), school principals (n = 30), school counselors (n = 30) and chemical health providers (n = 14) were pooled to create indices of social environmental norms, role models, social support and opportunities for non-use of alcohol. Each index was examined for its association with prevalences from 30 schools of alcohol use onset, last-month alcohol use, heavy alcohol use and last-year marijuana use in univariate and stepwise regression analyses. Increases in the levels of norms, role models and opportunities for non-use predicted decreases in alcohol use prevalences. The explanatory power of the examined constructs in multivariate analyses was acceptably high (R2: 38-53%). These findings further support the notion that community-wide efforts need to be launched to affect changes in the normative, role model and opportunity structures of adolescents' social environments in order to curb adolescent alcohol and drug use.