Social norms are key predictors of college student drinking. Additionally, the social reasons for consumption (i.e. social drinking motives) are important to understanding drinking behaviour. This study investigated the effects of social norms and social motives on alcohol consumption. A total of 229 college students completed an online questionnaire assessing their drinking behaviour, social drinking motives and their perceived drinking social norms. Drinking social norms were assessed as descriptive norms (i.e. the individual s perceived prevalence of alcohol consumption), and injunctive norms (i.e. the individual s perceived approval of drinking by their peers). Additionally, injunctive norms were further separated into distal (socially distant peers) and proximal (socially close peers). Hierarchical regression analyses revealed descriptive norms, proximal injunctive norms and social motives all independently predicted alcohol consumption. Additionally, the relationship between proximal injunctive norms and consumption, and descriptive norms and consumption was mediated by social motives. Lastly, there was a significant three-way interaction between descriptive norms, distal injunctive norms and social motives on drinking. Consideration of both the individual factors and the complex interplay between social norms and social motives on alcohol consumption is necessary to further understand drinking behaviour, and to develop more effective alcohol harm-reduction strategies.