This study examined the relationships between adolescent alcohol use and outcome expectancies and descriptive norms for a sample of American Indian and white youth living on or near reservations. Three outcome expectancies proposed by the theory of normative social behavior (perceived benefits to self, perceived benefits to others, and anticipatory socialization) were examined. Survey data were collected from high school students in the 2009-2010, 2010-2011, and 2011-2012 school years. Stronger descriptive norms for use and higher perceived benefits to self from use were associated with alcohol use in the last month, drunkenness in the last month, and binge drinking. Perceived benefits to self also moderated the relationship between descriptive norms and both alcohol use in the last month and binge drinking, and the effect of descriptive norms on use became more robust as perceived benefits to self increased. Outcome expectancies of perceived benefits to others and anticipatory socialization did not moderate the relationship between norms and alcohol use. Implications for prevention are discussed.