Background and Objectives: Despite the advancement of health science and its expansion, the number of elderlies is increasing annually throughout the world, highlighting the necessity of paying attention to the issue of increasing the psychological well-being of senior citizens. Therefore, the present study was conducted to determine the role of emotion regulation and spirituality in predicting the psychological well-being of the elderlies. Methods: This descriptive-correlational study was performed on the elderlies living in the nursing homes in Qazvin, Iran, in the (...) summer of 2020. The samples were selected using the Krejcie and Morgan Table and availability sampling method. The questionnaires that were used as the tools of this research included the Emotion Regulation Scale, Spiritual Attitude Scale, and short-form of Psychological Well-being Scale. The collected data were analyzed in the SPSS software using Pearson correlation coefficient and multiple linear regression test. In this study, the significance level was considered 0.05. Results: The results showed psychological well-being had a direct and significant relationship with emotion regulation and its components, namely reappraisal and suppression. Moreover, psychological well-being showed a direct and significant relationship with spirituality and its components, including spiritual attitude and spiritual ability. Based on the findings of the standardized regression coefficient, the components of emotion regulation, including reappraisal and suppression, and those of spirituality, namely spiritual attitude and spiritual ability, could positively predict the psychological well-being of the senior citizens. Conclusion: According to the results of this study, the improvement of the characteristics of emotion regulation and provision of the grounds for the spirituality of the elderlies can boost the psychological well-being of the elderlies. (shrink)