This qualitative study was designed to explore the definition of ethnic identity of the Dusuns in Brunei Darussalam from the perspective of Shamsul A.B.'s (1996) 'everyday-defined' social reality. The purpose of this study was twofold. Firstly, by employing Phinney's (1996) formulation of ethnic identity, this study examined the existence of core components of ethnic identity, namely, ethnic self-identification, ethnic involvement, positive attitude towards ethnic group, and sense of belonging in the life of the Dusuns. Secondly, by utilizing Phinney's (1996) three-stage model of ethnic identity formation, this study investigated the relationship between core components and the formation process of ethnic identity. Twenty-six Dusun informants ranging in age from 8 to 80 years old were interviewed for the purpose of this study. The analysis of the interview data revealed that all core components exist and evolve in the life of the Dusuns. Different perspectives towards core components can also be identified across different age groups. Adult informants contested the relevance of ethnic involvement in view of socio-cultural transformations that occurred within the ethnic group, whereas younger Dusuns were not able to extend sense of belonging outside their family. These findings lead to the identification of family and historical contexts as influential factors that shape the ways the informants experienced the ethnic identity components. Further, the findings of this study indicate the relationship between core components and the formation process of ethnic identity. Sense of belonging and community is only evident in the experience of older informants, sufficient to help them reach the stage of achieving ethnic identity. This also shows a positive sequential relation between the stages in Phinney's ethnic identity model and the age of the informants. Interestingly, evidence on internalized sense of belonging reveals the fact that an individual could still attain ethnic identity achievement even without experiencing all components of ethnic identity. Once again, this study suggests contextual factors play a role in the stage progression of the Dusuns ethnic identity.