Introduction. Volunteerism represents an important aspect of productive aging, yet existing research has not fully explained the differences in later-life volunteerism between Asian midlife and older adults and other ethnoracial groups after accounting for socioeconomic resources. To address this gap, this study examined whether religious involvement and immigration status, conceptualized as traditional culture-related factors, help explain disparities in both formal and informal volunteerism among U.S. adults aged 50 to 75, enabling a comparison between Asian midlife and older adults and other ethnoracial groups. Methods. Data were obtained from pooled waves of the Health and Retirement Study (2004-2020), utilizing a cross-sectional sample of adults aged 50 to 75. Logistic regression models were used to estimate the odds of formal and informal volunteerism across ethnoracial groups, with Asian populations as the reference category. Models were sequentially adjusted for demographic characteristics, health, work status, education, and income, followed by the inclusion of religion and immigration status. Results. Higher religious involvement was associated with increased odds of both formal (OR = 2.023, p < .001) and informal volunteerism (OR = 1.219, p < .001), while being an immigrant was associated with lower odds of formal (OR = .593, p < .01) and informal volunteerism (OR = .432, p < .001). After accounting for these factors, previously observed differences between Asian and White populations in both forms of volunteerism were no longer statistically significant, suggesting that religion and immigration status partially explain these disparities. However, differences between Asian individuals and Hispanics persisted (formal: OR = .483, p < .01; informal: OR = .551, p < .05). Conclusion. These findings suggest that religion and immigration are especially important for understanding how patterns of volunteerism among Asian midlife and older adults compare with those of other ethnoracial groups in later life.