Background: Nowadays, the quality of life of hemodialysis patients has decreased, which doubled the need for educational interventions. Objectives: The current study investigated the effect of positive thinking training on different dimensions of quality of life of hemodialysis patients. Methods: This is a controlled clinical trial study conducted on 70 hemodialysis patients in Fasa, Fars province, in 2019. The patients were selected using the simple sampling method. Then, they were divided into two groups of intervention (n = 35) and control (n = 35). After obtaining informed consent, the researchers asked the participants to complete the SF-36 Quality of Life Questionnaire. The intervention group was trained positive thinking skills in 8 workshop sessions; each lasted for 90 minutes. Data were analyzed using SPSS version 20. To analyze the data, statistical tests such as chi-square, Kolmogorov-Smirnov, independent, and t-test were used. Results: The mean and standard deviation of the patients’ quality of life in the intervention group increased from 35.95 ± 10.07 to 55.98 ± 11.71 (P < 0.001). The changes in patients’ quality of life before and after the intervention were also assessed in 8 dimensions, which showed that the quality of life of the patients did not change significantly in terms of physical function (P = 0.42) and physical pain (P = 0.62), but for other dimensions, it was significantly increased (P < 0.001). Conclusions: Positive thinking training improved the quality of life of hemodialysis patients, particularly in the dimensions of the emotional role, emotional health, energy and vitality, social performance, and general health is recommended.