A survey was conducted to determine which socio-cultural and psychosocial variables had the ability to discriminate adolescent drinking behavior at four different age groups. A total of 3,017 sixth, eighth, tenth, and twelfth grade students in the Southeast participated in the study. Those students who were classified as moderate to heavy drinkers were more likely to be White, male, had higher scores on an alcohol knowledge test, were more liberal in their attitudes toward alcohol use, drank at an earlier age, and had friends who drank. When all predictor variables were considered as a group, the two most predominant characteristics for explaining student drinking behavior were peer behavior and attitudes toward alcohol. Parental drinking behaviors were significant for the younger students, but compared to the peer and attitude variables, their contributions to group separation were minor. Efforts to curb moderate or heavy drinking among adolescents should focus on the peer influences of adolescent drinking and related risk factors associated with problem drinking.