Studies on multiculturalism and polyculturalism are typically carried out in multicultural societies; studies on relatively homogeneous societies are rare. In this study, we use a mixed-method approach to explore how the two lay theories of culture are understood in a culturally homogeneous community (Wonosobo) in a multicultural country (Indonesia). In Study 1, data gathered using focus group discussions with 36 university students were analyzed using inductive thematic analysis. In Study 2, 264 university students answered questionnaires on lay theories and intergroup attitudes toward Chinese-Indonesians. Both studies suggest an understanding of the two lay theories of culture, but that multiculturalism was more well-defined in the students’ responses in the focus group discussions and more strongly endorsed in the questionnaire data. Multiculturalism was often discussed with reference to the national ideology of Pancasila and was also associated with greater stereotyping of Chinese-Indonesians. Polyculturalism was typically mentioned only with reference to multiculturalist ideas and had negative intergroup consequences when interacting with multiculturalism. The results are discussed as indicating some negative intergroup implications for the two lay theories of culture within the culturally homogeneous community.