Primal world beliefs ("primals") capture individuals' basic understanding of what sort of world this is. How do children develop beliefs about the nature of the world? Is the world a good place? Safe or dangerous? Enticing or dull? Primals were initially introduced in social and personality psychology to understand beliefs about the world as a whole that may influence well-being and personality. This article introduces the concept of primals to developmental scientists and reviews preliminary research examining how primals relate to sociodemographic and well-being indicators. The article then situates the concept of primals in some classic developmental theories to illustrate testable hypotheses these theories suggest regarding how primals develop. Understanding how individuals develop basic beliefs about the nature of the world deepens insights into the human experience, including how malleable these beliefs might be and how they may be influenced by, and in turn influence, other domains of development.