This article integrates knowledge from health psychology, life course development, and social psychology to outline a theoretical framework for identifying, investigating, promoting, and evaluating beneficial action. Beneficial action is defined as a subset of prosocial (motivated to benefit others that may include self-interest) and altruistic (prosocial motivation without self-interest) behavior that uses consequential (scientific) knowledge to increase freedom within the global population. Beneficial action theory seeks to increase political and social actions that are planned and evaluated to ensure key tasks in human development. Central among these is the broadening of social identity to ensure that the human potential to use science to modify the natural environment achieves benefits for the global population. This article presents a theoretical framework for conceptualizing the psychological processes that underlie the development, application and evaluation of beneficial action for individuals and populations. The need to conceptualize beneficial action arises from 3 related observations. First, the certainty of knowledge of the beneficial outcome of a specific human action increases the moral motivation to engage in that action. For example, there is consensus among psychologists and other professions that it is unethical to engage in therapeutic practices that have evidence for neutral or harmful consequences. Second, due to the rapid increase in scientific knowledge, the range of human action that has scientifically ascertainable consequences is rapidly expanding. Third, advancing scientific knowledge means that human actions have increasingly powerful consequences for humanity and the natural world, warranting careful consideration of how to ensure global population benefits.