This paper imagines and explains the essence of Oromo self-knowledge in relation to Oromummaa—Oromo culture, identity, and human agency at the personal, interpersonal[i] and collective (national)[ii] levels. It specifically explains the relationship between Oromo national and sub-identities before and after colonialism, the uneven development of Oromummaa, and Oromo organizational problems. This paper also suggests some steps that should be taken by Oromo leaders, nationalists, and activists in order to overcome the problem of uneven development of Oromo nationalism and to build an effective national political leadership, increasing the organizational capacity of Oromo society so it will be able to achieve self-determination and human liberation. Let me start my discussion with the concept of Oromummaa—a manifestation of Oromo national culture, identity, and nationalism.