Diabetes is one of the most common chronic diseases, which has a negative effect on the quality of life. Objectives:The aim of this study was to investigate the effectiveness of training based on positive psychology on the quality of life of patients with type 2 diabetes. Materials and Methods:This quasi-experimental study had a Pre-test-Post-test with a control group and a follow-up design. The sample was selected through the convenience sampling method from patients with type 2 diabetes in Hazrat Ali Health center in Isfahan in 2017; then, they were randomly divided into 2 groups (each group contained 15 individuals). The experimental group was trained with positive psychology and the control group did not receive any treatment. Both groups were evaluated before and after the intervention and at the follow-up stage, using the World Health Organization Quality of Life questionnaire. The data were analyzed by the analysis of variance with repeated measurements. Results:The results showed that positive psychological education had a significant influence on the quality of life and mental health area, social relations, and environmental health in patients with type 2 diabetes. Also, there was a significant difference between the experimental and control groups; but in the physical health area, there was no significant difference between the experimental and control groups (P<0.001). Conclusion:Positive psychological education effectively improves the quality of life of patients with type 2 diabetes. Therefore, it is recommended to use this treatment approach to help improve the quality of life of these patients.