Aim: The present study aimed to examine the effectiveness of mind games in improving psychological adjustment in older men. Methods: The present quasiexperimental study had a pretest-posttest design with the control group. The statistical population consisted of 30 older retired men in District 5 of Tehran in 2019 with lower scores in the Bell Psychological Adjustment Inventory (1961) and they were randomly put into two 15-participant experimental and control groups. The experimental group received an intervention method of the mind games for eight 90-minute sessions and the results were analyzed using the univariate ANCOVA. Results: The results indicated that mind games improved psychological adjustment (P=0. 001, F=34. 80) and subscales, namely home adjustment (P=0. 001, F=31. 61), health adjustment (P=0. 001, F=22. 95), social adjustment (P=0. 003, F=10. 64), emotional adjustment (P=0. 001, F=13. 78), and job adjustment (P=0. 005, F=9. 47) in the older participants in the control group. Conclusion: According to the results, it seems that playing mind games improved adjustment in older people; hence, we suggest using this simple, costeffective, and easy-to-use method.