In this article, we postulate that belief understanding unfolds in two steps over ontogenetic time. We propose that belief understanding begins in interactive scenarios in which infants and toddlers respond directly and second-personally to the actions of a misinformed agent. This early understanding of beliefs is practical and grounded in the capacity for perspective-taking. Practical belief understanding guarantees effective interaction and communication with others who are acting on false assumptions. In a second step, children, at preschool age, acquire the capacity (...) to reflect on and arrive at third-personal judgments about a misinformed agent’s perspective. This capacity is theoretical and grounded in the ability to “confront” perspectives. It allows children to understand that beliefs can misrepresent the state of the world and to predict what (past, future, or hypothetical) actions follow from these beliefs. We conclude with ideas on how practical perspective-taking develops into theoretical perspective-confronting in early ontogeny. (shrink)