ABSTRACT: BACKGROUND:Sleep is a natural, restorative, physiological process that is characterized by perceptual disengagement from and unresponsiveness to whatever going around, which is reversible. Sleep quality refers to a sense of being rested and refreshed after waking up from sleep. People living with HIV/AIDS (PLWHA) are vulnerable to poor sleep quality as they suffer from social stigma and Anti-Retroviral drug side effects. The study aimed to examine the quality of sleep and its associated factors among people living with HIV/AIDS attending Anti-Retroviral Therapy (ART) clinic at Hawassa University comprehensive specialized hospital. METHOD:Institutional based cross-sectional study was conducted among PLWHA attending ART clinic at Hawassa University comprehensive specialized hospital from May 1-30, 2019. A systematic random sampling technique was used to select an estimated 422 study participants and data was collected using interviewer-administered technique. Sleep Quality was assessed using the Pittsburgh Sleep Quality Index (PSQI). Data were entered and analyzed using SPSS 22 software. Bivariable and multivariable logistic regression model was fitted to identify factors associated with quality of sleep. An adjusted odds ratio with a 95% confidence interval was computed to determine the level of significance with P-value less than 0.05. RESULT:Out of 422 respondents, 389 participated in the study giving a response rate of 92.1%. The prevalence of poor quality of sleep among study participants was found to be 57.6% (95% CI: 54.72, 60.48). 31.9% (124) and 30.6% (119) of study participants had anxiety and depression respectively. Being between the age of 55-64 years (AOR = 5.7, 95% CI (1.9, 17.8), Age ? 65 (AOR:6.6, 95% CI (1.2, 36.9), Monthly income <1656 Ethiopian Birr (ETB) (AOR = 2.17, 95% CI (1.06, 4.4), having anxiety (AOR = 4.4, 95% CI (2.12, 9.2), having depression (AOR = 4.97, 95% CI (2.28, 10) and poor social support (AOR = 2.9, 95% CI (1.16, 7.3) were factors associated with poor quality of sleep. CONCLUSION:The prevalence of poor quality of sleep among PLWHA was significantly high. Average monthly income, age, anxiety, depression, and social support were found to be significantly associated with poor sleep quality. Health care professionals working at the ART clinic need to assess the sleep pattern of ART clients, give psychoeducation on the prevention and management of sleep pattern problems.