BACKGROUND: Subjective well-being (SWB) is a crucial measure of life quality in older adults. Understanding its relationship with frailty may inform strategies to promote healthy aging. METHODS: We analyzed data for older adults aged ≥60 years old from Waves 3 and 4 of the China Health and Retirement Longitudinal Study. SWB was measured based on participants' self-reported overall satisfaction with life. A frailty index was developed using the deficit accumulation approach. We conducted a cross-sectional Poisson regression to investigate the relationship between SWB and counts of frailty deficits. Additionally, we conducted a longitudinal analysis to determine the 3-year relative risk of clinically significant frailty progression or mortality for different levels of SWB. The analyses were adjusted for individual weights, including adjustments for household nonresponse. RESULTS: The cross-sectional analysis included 9 702 individuals. After adjusting for covariates, lower baseline life satisfaction was associated with higher counts of frailty deficits (mean deficit counts ratio [95% confidence interval]: 1.66 [1.54, 1.78] for "not satisfied" and 1.06 [1.02, 1.10] for "somewhat satisfied" relative to the reference "very satisfied"). The longitudinal analysis included 8 599 individuals. Participants who were "not satisfied" with life at baseline were at a greater risk of frailty progression compared with those who were "very satisfied" (risk ratio: 1.16 [1.00, 1.35]). CONCLUSIONS: Our study finds that a lower level of SWB is associated with more severe frailty. It is also associated with frailty progression or death. These results emphasize that both psychological well-being and physical health are essential components of healthy aging.