This chapter reviews work on the shared psychological functions of science and religion. In doing so, we focus on three of these functions that are of particular importance to human functioning: explanation, control, and meaning. The research that is reviewed indicates that both belief systems can help to address motivational needs pertaining to these functions, albeit in different ways and with somewhat different degrees of success. Morality and mortality are two central domains within which this notion is further explored. We conclude that the psychological functions that belief systems fulfil form a central component of both science and religion, as well as of their complicated relationship.