Evolutionary theory offers a framework for organizing, expanding, and refining psychological theories of moral development. Prosocial behavioral dispositions evolved in early humans (and other animals) because they helped them reap the adaptive benefits of social living. The emotional reactions that accompanied these dispositions endowed early humans with a primitive sense of morality, which was refined and elaborated when they acquired the capacity to make moral judgments. Moral norms evolved as products of strategic social interactions among members of groups who experienced confluences and conflicts of interest. Moral beliefs and moral standards are products of automatic and controlled information-processing and decision-making mechanisms. To understand morality, we must attend to the adaptive problems it evolved to solve. Moral reasoning is a tool that may be used to achieve moral and immoral goals.