Humans rely on social interaction to achieve many important goals. These interactions rely on people’s capacity to understand others’ mental states: their thoughts and feelings. Do different cultures realize this ability in different ways, or do universal principles describe how all peoples understand mental states? Here we investigated mental state representation in 57 countries, 17 languages, and 4 historical societies. We quantified mental state meaning by analyzing large bodies of text produced by each culture. We then tested whether a theory of mental state representation – the 3d Mind Model – could explain which mental states were similar within each culture. The model explained mental state representation in all studied cultures, indicating that universal principles describe how people understand other minds.