This article explores the role of religion in human capital investments and the family in the United States, based on analyses of microlevel data. The economic perspective views an individual's religious affiliation as affecting economic and demographic behavior because the norms and teachings of various faiths influence the perceived benefits and costs of numerous decisions that people make over the life cycle, including choices regarding the pursuit of investments in secular human capital, cohabitation, marriage, divorce, family size, and employment. These decisions are closely interrelated, so when religious teachings directly influence any one of them, all others are indirectly affected. Consistent with existing structures of perceived benefits and costs, several religious groups in the United States exhibit patterns of economic and demographic behavior that differ significantly from those of mainline Protestants. A higher level of religious participation can affect economic and demographic behavior by accentuating the effects of affiliation. The article also examines patterns of non-marital sex and divorce among conservative Protestants and discusses the role of religion in the second demographic transition in the United States.