Purpose: Good self-management in patients with diabetes will help them to maintain their well-being and quality of life, and the control of risk factors will make it possible to manage disease symptoms and to prevent complications. This study was carried out to determine the self-efficacy levels of patients with type 2 diabetes regarding their care and the factors affecting them and to examine the relationship between patients’ self-efficacy and quality of life. Methods: This study used a cross-sectional design and was carried out with a total of 342 patients with type 2 diabetes. The Diabetes Management Self-Efficacy Scale (SES) was employed to evaluate diabetes self-efficacy levels of the patients, and the WHO Quality of Life Scale-Brief Form was used to evaluate their quality of life. Results: The mean of the scores that the patients obtained from the SES scale was 64.16 ± 12.09. Diabetes self-efficacy was higher in patients who were married, were university graduates, had received training/information related to the disease, did not have any other chronic diseases, and did not exhibit any complications (p <0.05). The quality of life of patients who did not exhibit any complications and were receiving oral antidiabetic medication was higher (p <0.05). Conclusions: A weak and positive correlation was found between the mean of the overall diabetes selfefficacy scale scores and the subscales of the quality of life scale. As the diabetes-related self-efficacy of the patients increased, their quality of life increased, as well.