The main purpose of this paper is to theorize Oromummaa by conceptualizing it on different levels and offering theoretical insights and critical analysis of the Oromo national movement in relations to the struggles of other colonized peoples. Theorizing and conceptualizing Oromummaa specifically in relations to the ideological problem of the Oromo national movement and that of the others require recognizing the need to transform thinking and scholarship in Oromo politics and studies in order to critically and thoroughly assess the prospects for Oromo politico-cultural transformation and liberation. Theoretically, critically, and practically comprehending Oromummaa as Oromo nationalism, national culture, and identity is essential because the Oromo nation is the fulcrum for bringing about a fundamental transformation in the Ethiopian Empire and the Horn of Africa in order to establish sustainable peace, development, security, and an egalitarian multinational democracy.