The Strong African American Families Program, a universal preventive intervention to deter alcohol use among rural African American adolescents, was evaluated in a cluster-randomized prevention trial. This 7-week family skills training program is based on a contextual model in which intervention effects on youth protective factors lead to changes in alcohol use. African American 11-year-olds and their primary caregivers from 9 rural communities (N = 332 families) were randomly selected for study participation. Communities were randomized to prevention and control conditions. Intent-to-treat analyses indicated that fewer prevention than control adolescents initiated alcohol use; those who did evinced slower increases in use over time. Intervention-induced changes in youth protective factors mediated the effect of group assignment on long-term changes in use.