Background: Misperceptions on the higher rates of peer alcohol use are predictive of increased personal use among university students. Objectives: This study aims to assess the prevalence, perceived peers' social norms and other predictors of alcohol use in a sample of Turkish university students. Methods: This study is established upon the baseline Turkish data on alcohol use of the project Social Norms Intervention for the prevention of Polydrug usE (SNIPE). The data was obtained by a self-reported, online questionnaire from 858 students of Marmara University who were registered to the study web page. Results: Alcohol use and drunkenness rates were 62.6%, and 40.9%, respectively. Twenty point two percent of students reported drinking alcohol at least once a week in the last two months. Majority of students (70.4%) reported that religion has an important or very important role in their lives. Perceived higher frequency of peer alcohol use (p<0.000) and drunkenness (p<0.000) were significantly associated with personal alcohol use frequency. Tobacco use rate was 60.2% and positively associated with alcohol use frequency (p<0.000). In all participants, male gender (OR: 1.56; 95% CI: 1.07-2.28), giving less importance to religion (OR: 20.91; 95% CI: 10.95-39.95), tobacco use everyday/almost everyday (OR: 17.88; 95% CI: 9.33-34.29), perceived positive peer attitude towards alcohol use (OR: 2.192; 95% CI: 1.25-3.82) and perceived higher frequency of peer alcohol use (OR: 3.487; 95% CI: 1.66-7.31) were found to be associated risk factors for alcohol use. Age (OR: 1.186, CI 95%: 1.03-1.36) and perceived positive peer attitude towards alcohol use (OR 3.86, CI 95%: 1.84-8.09) were the additional risk factors among female student whereas perceived positive peer alcohol use frequency (OR: 8.08, CI 95%: 2.40-27.10) among male students. Discussion: As the first study conducted in Turkey applying social norms theory, our results indicate the noticeable misperceptions of students regarding their peers' alcohol use. Based on our results, targeting both tobacco and alcohol use, and a gender-sensitive approach employing social norms interventions may enhance the preventive strategies for risky alcohol use among university students.