Objective: Sleep disorders affect 54.9% of gynaecologic cancer survivors. The effect of treatment methods on sleep quality is not clear. This study evaluated the sleep quality of survivors of endometrial cancer and compared the effects of different treatments on sleep quality. Materials and Methods: Patients were categorised as surgery (group 1), surgery + brachytherapy (BRT) (group 2), surgery + external beam radiation therapy (EBRT) (group 3), and surgery + EBRT + BRT + chemotherapy (group 4). Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI) questionnaire. The PSQI was completed by the participants before surgery, 1, 3, and 6 months after each treatment was completed. The PSQI scores were compared between the different measurement times and different study groups. Results: This study enrolled 114 patients with a mean age of 58.1±11 years. The number of participants in each group was 53 (46.5%), 14 (12.3%), 12 (10.5%), and 35 (30.7%), respectively. At baseline, 28 (24.6%) patients reported poor sleep quality. The mean PSQI score reached the maximum level at the second measurement and decreased slightly during follow-up and the change in the PSQI score was significant (p=0.001). Group 3 and group 4 had significantly higher scores from baseline (p<0.008). At time point 3, the differences between the groups were significant. At time point 4, the most prominent effect of treatment on sleep quality was observed in patients with combined chemo-radiotherapy when compared with the other study groups. Conclusion: Most survivors of endometrial cancer are affected by poor sleep quality during their treatment. To improve these patients’ quality of life, this disorder must be considered at each visit and tailored care plans should be developed to meet the women’s needs. Further studies are needed to evaluate the long-term results of sleep quality on patients with endometrial cancer.