Objective: The prevalence of poor sleep quality has been greatly escalating over the past years, along with the surging of type 2 Diabetes Mellitus (DM). The aging population is most concerned as sleep quality is notably impaired and influences the diabetic condition. This study aimed to observe the sleep quality and factors related to poor sleep quality in elderly patients with type-2 DM. Materials and Methods: A cross-sectional study of patients with type 2 DM, aged 60 years and above was conducted. The questionnaires included demographic data, the Thai version of the Pittsburgh Sleep Quality Index (T-PSQI), the Thai version of the Diabetic-39, and the Thai Geriatric Depression Scale-15. Factors associated with sleep quality were analyzed using the logistic regression model. Results: Among 385 participants with a mean age of 67 years old was 63.90% female. The prevalence of poor sleep quality was 9.88%. No association was found between sleep quality and glycemic levels. The related factors for poor sleep quality were sex (aOR = 2.57, p = 0.035, 95%CI = 1.06-5.93), body mass index (aOR =1.09, p = 0.028, 95% CI = 1.00-1.20), and diabetic complications. Diabetic retinopathy showed highest odd ratio (aOR = 6.28, p = 0.021, 95% CI = 1.32-29.94). Conclusion: The prevalence of poor sleep quality was low in the current study. We found a strong association between diabetic complications and poor sleep quality. Evaluation of sleep quality may help to enhance overall health and care for diabetic geriatric patients.