Objective: Smartphones have become the most preferred devices of today with the development and widespread use of social media networks. The aim of this study is to determine the relationship between social network usages and sleep quality among university students. Methods: Overall, 1369 university students (791 females and 578 males) were included in the study. In the cross-sectional study with self-report questionnaires [Sociodemographic Questionnaire, Pittsburg Sleep Quality Index (PSQI), and Smartphone Addiction Scale Short Version (SAS-SV)] were utilized. Descriptive and inferential statistics were done. Results: The mean score of SAS-SV and PSQI was calculated based on demographic variables and statistically significant differences were found between the frequ-ency of smartphone change, monthly smartphone bill, smartphone addiction, and sleep quality. It was statistically significant when students daily Facebook, Twitter, Instagram, Snapchat, Swarm, and Foursquare users times were compared with the mean score of SAS-SV and PSQI. Conclusions: In conclusion, our study thought that overuse of smartphones along with social media networks in college students is potentially addictive and will affect sleep quality negatively. It was also discussed which popular social media networks increased smartphone addiction risk and affected sleep quality. Due to the limited number of studies in the literature on this subject, we think that our study will contribute to the field. [Anadolu Psikiyatri Derg 2020; 21(2.000): 141-148]