Where does morality come from? Why are moral judgments often so similar across cultures, yet sometimes so variable? Is morality one thing, or many? Moral Foundations Theory (MFT) was created to answer these questions. In this chapter, we describe the origins, assumptions, and current conceptualization of the theory and detail the empirical findings that MFT has made possible, both within social psychology and beyond. Looking toward the future, we embrace several critiques of the theory and specify five criteria for determining what should be considered a foundation of human morality. Finally, we suggest a variety of future directions for MFT and moral psychology.