Despite the rapid growth of the gambling industry over the last 40 years, there have been few large-scale, nationally representative longitudinal studies of gambling among young adults. We use data from the National Longitudinal Study of Adolescent to Adult Health to investigate whether and how the gambling behavior of young adults is associated with their religious beliefs and practices during adolescence. We find that young adults who grew up as conservative Protestants, mainline Protestants, Mormons, and Jehovah's Witnesses; those were raised in a community with a higher percentage of conservative Protestants; and those who attended religious services weekly are less likely to have ever gambled. Among gamblers, young adults who attended religious services up to three times per month as adolescents are more likely to experience gambling problems than those who never attend. Notably, accounting for a young adult's propensity for risk-taking behavior does not explain the associations between religion and gambling.