Poor family cohesion and elevated adolescent aggression are associated with greater alcohol use in adolescence and early adulthood. In addition, evocative gene-environment correlations (rGEs) can underlie the interplay between offspring characteristics and negative family functioning, contributing to substance use. Gene-environment interplay has rarely been examined in racial/ethnic minority populations. The current study examined adolescents' polygenic risk scores for aggression in evocative rGEs underlying aggression and family cohesion during adolescence, their contributions to alcohol use in early adulthood (n = 479), and differences between Mexican American and European American subsamples. Results suggest an evocative rGE between polygenic risk scores, aggression, and low family cohesion, with aggression contributing to low family cohesion over time. Greater family cohesion was associated with lower levels of alcohol use in early adulthood and this association was stronger for Mexican American adolescents compared to European American adolescents. Results are discussed with respect to integration of culture and racial/ethnic minority samples into genetic research and implications for alcohol use.