This research investigated the impact of perceived social norms about voting on college students' intention to vote. College students were asked about their perceptions of the frequency of others' voting (descriptive norms) and the importance of voting to others (injunctive norms), as well as their own intention to vote in an upcoming election. Several weeks later, students were randomly assigned to conditions where the information about the percentage of college students who voted in the last election was manipulated. Above and beyond the influence of typical predictors of voting behavior, perceived social norms about voting were found to be a significant predictor of intention to vote. Perceived importance and frequency of voting to close friends and family were consistent predictors of intention to vote. Similarity to other students moderated the relationship between descriptive and injunctive norms of student voting and intention to vote. Giving students information about the prevalence of college student voting increased the crystallization (level of agreement) of the injunctive norm for college student voting. The present findings suggest that efforts to motivate students to vote should take advantage of the social connections among friends and families in order to maximize the effect of descriptive or injunctive normative campaigns.