Background and Objectives: We examined the associations of religious attendance during childhood (C-RA) and adulthood (A-RA) with alcohol involvement (ever drinking, timing of first alcohol use, and alcohol use disorder [AUD]) in White and Black female twins. As genetic and environmental factors influence religious attendance and alcohol involvement, we examined the extent to which they contribute to their association. Methods: Data on 3,234 White and 553 Black female twins (18–29 years) from the Missouri Adolescent Female twin Study. Significant correlations between C-RA or A-RA and alcohol involvement were parsed into their additive genetic, shared environmental, and individual-specific environmental sources. Results: C-RA was associated with ever drinking and timing of first alcohol use in Whites. A-RA was associated with ever drinking and AUD in both Whites and Blacks. Shared environmental influences did not contribute to alcohol or religiosity phenotypes in Blacks. In Whites, the association between C-RA and alcohol was due to shared environmental influences, whereas the association between A-RA and alcohol was attributable to additive genetic, shared environmental, and individual-specific environmental sources. Individual-specific environment and genetics contributed to associations between A-RA and ever drinking and AUD, respectively, in Blacks. Conclusions: Factors other than C-RA contribute to lower rates of alcohol involvement in Blacks. Shared environment does not contribute to links between A-RA and alcohol involvement in Blacks. Scientific Significance: The protective impact of childhood religiosity on alcohol use and misuse is important in Whites and is due to familial factors shared by religiosity and alcohol involvement. (Am J Addict 2017;26:437–445).