Objective: Research shows that poor sleep quality and smartphone addiction are common problems among university students. This study was planned to evaluate the quality of sleep in students at Pamukkale University and to investigate its relationship with smartphone addiction. Methods: This cross-sectional study was carried out at the university campus in 2017-2018. Its dependent variable was low sleep quality. Independent variables were smartphone addiction, features related to smartphone addiction, socio-demographic features and other questioned features. The total number of students attending normal education in seven faculties and two colleges for four years was 20862. The minimum sample size of the study was calculated as 1088. Smartphone Addiction Scale-Short Version (SAS-SV) and Pittsburgh Sleep Quality Index (PSQI) were used. The data were analyzed with the SPSS program. Results: The mean age was of the participants 21.39 ± 2.21. The sleep quality of students with a PSQI total score of more than five was defined as ‘poor’. The frequency of poor sleep quality was 52.4%. The frequency of smartphone addiction was 34.6% according to the SAS-SV scale. It was found that the frequency of poor sleep quality was significantly higher in students with smartphone addiction compared to others. Conclusion: Smartphone addiction was found as one of the risk factors for poor sleep quality. doi: https://doi.org/10.12669/pjms.37.1.3130 How to cite this:Ozcan B, Acimis NM. Sleep Quality in Pamukkale University Students and its relationship with smartphone addiction. Pak J Med Sci. 2021;37(1):206-211. doi: https://doi.org/10.12669/pjms.37.1.3130 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.