The words of different languages partition the world in strikingly different ways. Yet many people are unaware ofsuch differences, believing that some of the words of their native language pick out discrete categories based in nature. Weinvestigated whether knowledge of cross-linguistic semantic diversity—putatively inherent to bilingualism—can reduce suchessentialist beliefs. In three experiments, we found (a) that bilinguals were less likely than monolinguals to judge membershipfor animal categories in essentialist terms, (b) that explicit exposure to cross-linguistic semantic diversity, independent ofbilingualism, yielded similar effects, and (c) that this manipulation reduced essentialist beliefs about social categories as well.Together, our findings suggest that learning about how languages differ in their semantic systems—a form of metalinguisticknowledge—can lead people to think about categories more flexibly. Implications for research on language and thought, andfor ameliorating the negative consequences of social essentialism, are discussed.