BACKGROUND AND OBJECTIVES: Although recent research has consistently shown that psychological resilience is positively associated with cognitive function among older adults, the underlying mechanisms are still largely unclear. In this study, we assessed the potential mediating role of physical activity between psychological resilience and cognition using a longitudinal, population dataset of US older adults. RESEARCH DESIGN AND METHODS: Data were derived from three time points (2010-2012, 2014-2016, and 2018-2020) of the Health and Retirement Study (HRS), with 8,296 older adults at baseline included (aged 65 or above). Cognitive function was measured by 35-point Telephone Interview Cognitive Screen (TICS). psychological resilience was measured using a previously established simplified resilience score. RESULTS: Psychological resilience at baseline was positively associated with physical activity at T2, 4 years later (β=0.08,SE=0.01,p<
0.001). In addition, physical activity predicted an increase in cognitive function from T2 to T3 (4 years to 8 years later) (β=0.05,SE=0.07,p<
0.001). Finally, a significant indirect effect of psychological resilience (T1) on cognitive function (T3) through physical activity from (T2) was observed (β = 0.01, 95% CI [0.01, 0.02], p <
0.001). DISCUSSION AND IMPLICATIONS: Physical activity may function as a protective factor for the cognitive functioning of older adults. This association is partially mediated by enhanced physical activity.