OBJECTIVE: Sleep quality is affected during pregnancy due to the reasons such as physical and hormonal chan-ges, anxiety, and increased abdominal discomfort due to growing fetus putting pressure on the diaphragm. In the present study, we aimed to assess the sleep quality in pregnant women, to evaluate the correlation betwe-en sleep quality and trimesters, and to identify possible factors which affect the sleep quality during pregnancy. MATERIALS AND METHODS: This is a cross-sectional and descriptive study included a total of 152 pregnant women who were admitted to Afyon Kocatepe Univer-sity, Ahmet Necdet Sezer Research and Training Hospital, Gynecology and Obstetrics outpatient clinic between December 2015 and February 2016. Data were collected in face-to-face meetings. Data were collected using Per-sonal Data Form, Pittsburgh Sleep Quality Index (PSQI), and Berlin Sleep Questionnaire (BSQ). RESULTS: The mean age of the patients was 27,59 ±5,59 years, and 70,4% of them were housewives. Educational level of the pregnant women participating in the study was secondary school or higher. According to body mass index (BMI) values, 20,4% of the pregnant women were obese. According to the PSQI scores, 55,92% had poor sleep quality (˃5). The mean PSQI score was 7,38±4,91. According to the BSQ scores, 44,07% of the pregnant wo-men had poor sleep quality (˃2). CONCLUSIONS: Our study results showed that overall sleep quality of the pregnant women changed based on the trimester, and the poorest quality of sleep was du-ring the third trimester. In addition, sociodemographic characteristics have an impact on the sleep quality. As sleep disturbances can lead to serious maternal and fe-tal complications during pregnancy, early diagnosis and appropriate treatment are required to reduce these poor outcomes.