Across two studies, we tested whether members of host communities (i.e., locals) can themselves simultaneously maintain their national culture maintenance and adapt toward cultural diversity (i.e., multiculturalism) in their own home country, supporting a bidimensional model of acculturation, or whether these strategies are incompatible, supporting a unidimensional model of acculturation. We modified the Vancouver Index of Acculturation (Multi-VIA) to assess locals’ national culture maintenance and multicultural adaptation within their own home country. Study 1 supported the bidimensionality of the Multi-VIA in an American sample (n = 218). Moreover, we found an oblique association between locals’ national culture maintenance and multicultural adaptation. In Study 2, we tested the Multi-VIA’s psychometric properties across three continent groups (North America, Europe, and Asia; N = 619). Multiple-group confirmatory factor analysis demonstrated good model fit for the entire sample. Nevertheless, the association between national culture maintenance and multicultural adaptation was orthogonal for Asians and oblique for Americans and Europeans. In addition, national culture maintenance predicted higher levels of locals’ life satisfaction, whereas multicultural adaptation was associated with less acculturative stress and greater intercultural sensitivity.