ABSTRACT The relationships between adaptive and maladaptive aspects of gender roles in predicting substance use were examined in a sample of 955 (450 boys, 505 girls) Mexican American 7th and 8th grade adolescents participating in a school-based substance use intervention. The moderating effect of linguistic acculturation, the mediating effects of antisociality, depressive symptoms, and adaptive and avoidant coping on gender role-substance use relationships were examined. Correlational and path analyses supported the Functional Model of Gender Roles that considers these roles as adaptive or maladaptive social coping strategies. For boys, the path analyses yielded significant direct paths from aggressive masculinity to composite alcohol, cigarette, and marijuana use measures, with all other effects of gender roles on substance use operating through the mediators. Bootstrapped mediation tests yielded significant indirect paths, where for boys the positive relationships between assertive and aggressive masculinity with substance use and the negative relationship of affective femininity with substance use were mediated through antisociality, which is predictive of increased substance use. For girls, the positive relationship between aggressive masculinity with cigarette and alcohol use and the negative relationship of affective femininity with alcohol and cigarette use were also mediated by adaptive coping, which is predictive of decreased substance use. A different set of significant indirect paths through avoidant coping connected assertive masculinity and submissive femininity to alcohol use for boys. For boys, the paths from affective femininity to antisociality and adaptive coping were found to be moderated by linguistic acculturation, with the negative correlation of affective femininity with antisociality and positive correlation of this gender role with adaptive coping being stronger in boys low in acculturation. In turn, the pathway from this acculturation by affective femininity interaction to substance use was found to be mediated by antisociality. The present analyses confirmed the importance of gender roles and their interaction with acculturation in predicting substance use in Mexican American adolescents. The analyses also were important in delineating functional mechanisms through which these gender roles have their effects, with implications for the design of interventions to reduce substance use in this population.