This study investigated understandings of national group belonging in relation to attitudes toward foreign and established outgroups in Mauritius. Representative data were collected among the three numerically largest ethno-cultural groups (Hindus, Muslims, and Creoles; Ntotal = 1770) and results confirmed a distinction between “being,” “doing,” and “feeling” Mauritian among all three groups, with some small differences for Creoles compared to Hindus and Muslims. Furthermore, “being” Mauritian was not significantly related to attitudes toward foreign and established outgroups. In contrast, the “doing” understanding was negatively associated with both attitudes, and the “feeling” understanding showed positive associations with both outgroup attitudes among all three participant groups. The findings make a novel contribution to the literature on how people understand national identity, how these understandings differ between ethno-cultural groups within a nation, and how these relate to attitudes toward foreign as well as established outgroups.