Background & objectives: The one-third of human’s lifetime is passed through sleeping Success and well-being of them is related to their sleep quality. The aim of this study was to assess the sleep quality and its related variables among students of the University of Mohaghegh-e-Ardabili.

Methods: In this descriptive-cross-sectional study, 400 students were selected by multi-stage cluster sampling to fill the researcher-made demographic questionaire and the Pittsburg Sleep Quality Index (PSQI). Data were analyzed by T-test, ANOVA and Pearson Correlation Coefficient test.

Results: Results showed the average bedtime of students was 00:26 AM awakeness time was 07:49 AM and awakeness before sleep was 26 minute and duration of actual sleep was 6 hours and 51 minutes. Total index of sleep quality (6.24) was higher than normal rate (>5) that indicates a sleep disorder in 214 (53.5%) of the students. There was no difference in index of sleep quality of students based on their gender but students residing in dormitory had lower sleep quality than who lived at home (p<0.01). Sleep quality of students have positive relationship with bedtime, and awakeness before sleep, and negative relationship with duration of actual sleep, and academic performance (p<0.01).

Conclusion: Poor sleep quality in the majority of students suggests the necessity of an especial attention of family and health proffesionals to prevention of adverse effects of low sleep quality and promotion of students’ biopsychosocial health.