Previous research has shown that adolescent peer groups play a role in maintaining and exacerbating demographic differences in achievement. However, there is still limited knowledge about the malleable factors that contribute to these achievement disparities. This short-term longitudinal study examined one such malleable factor--namely, perceived norms. Participants were 710 Asian American and Hispanic/Latino students in Grades 9 and 10 followed over 1 year. Normative perceptions and academic engagement were measured with adolescent self-report. Grade-point averages and standardized test scores were obtained from school records. Path analyses showed that injunctive norms (perception of the acceptability of academic effort), but not descriptive norms (perception of peers' typical academic effort), significantly accounted for racial/ ethnic group differences in self-reported engagement and standardized test scores. This study indicates that perceived norms may contribute to racial/ethnic differences in educational outcomes.