The interrelation of ecological and psychosocial risk factors and adolescent marijuana use is examined in this three-sample longitudinal data analysis. Participants included (a) white children from the northeast of the USA, (b) African-American and Puerto Rican adolescents from New York City, and (c) adolescents living in Colombia, South America. Adolescents were interviewed in their homes. Independent measures were from the ecological, personality, peer, and family domains. Logistic regression analysis showed that the majority of ecological variables was related to adolescent marijuana use. Hierarchical regression analysis demonstrated that the ecological domain was directly and indirectly related to adolescent marijuana use (via the family, peer, and personality domains). Intervention programs should focus on adolescents' unique ecological settings while targeting universal risk factors (e.g., low ego integration, low parental identification) which predict adolescents' marijuana use. Similarities among the ecological predictors of adolescents' marijuana use in three samples, across time and place, allow a more universal approach to the prevention of substance use.