Most high school adolescents have reported past year gambling, and males gamble more frequently and problematically than females. Ethnic minority adolescents appear to be gambling at a higher rate than Caucasian adolescents. There is evidence indicating that adolescent gambling outcome expectancies are correlated with gambling behavior, but limited evidence that this relation differs by gender. In the present study gender was evaluated as a moderator in the relation between gambling outcome expectancies and gambling behaviors in an African-American high school sample. Males gambled more frequently, gambled more problematically and held more positive gambling outcome expectancies than females. Gender was found to moderate the relations between gambling frequency and the expectations of material gain, affect, self-evaluation and parental approval. Gender also moderated the relations between gambling problems and expectations of affect and self-evaluation. These findings should inform future adolescent gambling prevention and intervention programs.