Multiculturalism and polyculturalism are two lay theories of culture that have been associated with some similar intergroup attitudes and behaviors. But other than the studies of Rosenthal and Levy in the United States, there have been no studies that directly distinguish between these two lay theories. In this study, we use confirmatory factor analysis procedures to show that multiculturalism and polyculturalism represent two distinct latent constructs among our 1,730 participants in six Asian cultural groups (China, Hong Kong, Indonesia, Macau, Malaysia, the Philippines). Moreover, we show that essentializing race is associated with endorsement of multiculturalism (but not polyculturalism) in five cultural groups (except Hong Kong). The results provide strong cross-cultural empirical evidence for the distinction between the two lay theories and, more importantly, point to aspects of the lay theory of multiculturalism that relate to why it is sometimes associated with stronger stereotyping and prejudice toward minority cultural groups.