Objective:To investigate the sleep patterns of dental students from different academic levels and to determine the effect of sleep patterns on the academic performance of students.Methods:A self-reported questionnaire was designed and distributed among 1160 students from clinical and non-clinical levels to measure the sleep-related variables and academic performance. The questionnaire included questions on demographics, sleep habits, sleep quality index (PSQI), and grade point averages (GPAs). Data were analyzed with standard statistical software (SPSS, Statistical Package for the Social Sciences, version 22, Chicago, IL, USA).Results:The response rate was 62%. Sixty five percent of the students described their sleep as good or very good, whereas 35% described their sleep as bad or very bad. The mean number of hours of sleep per night for all students was 5.85 ± 1.853 hours. The GPA had a significant negative correlation with PSQI scores. The clinical group showed a stronger negative correlation (P = −0.351) than the nonclinical group (P = −0.134).Conclusion:It can be concluded that dental students tend to have poor sleep quality, which is unknown to them. Poor sleep quality was associated with lower academic performance, especially in clinical years.