["Scandinavian Journal of Psychology, EarlyView. ", "\nABSTRACT\nPrevious research consistently highlights a positive relationship between pro‐sociality and well‐being, often mediated by autonomy. However, limited attention has been paid to exploring the temporal dynamics of this relationship across age cohorts and historical periods. This study conducts a cross‐sectional cohort analysis using global data from the World Values Survey (N = 360,244; 109 countries) to examine age and period effects across adulthood. The findings indicate that: (1) Pro‐sociality, autonomy, and well‐being generally decline with age, but tend to increase across more recent time periods. (2) The positive link between pro‐sociality and well‐being is stronger among older adults compared to younger adults, and was stronger in earlier periods compared to more recent times. (3) The mediating role of autonomy increases with age across different periods, but decreases across successive time periods when examined chronologically. The results underscore the importance of autonomy for older adults and reveal a declining contextual role of autonomy over time in the relationship between pro‐sociality and well‐being. Implications, limitations, and future directions are discussed.\n"]