Since the coming of Ethiopian People’s Revolutionary Democratic Front (eprdf) into power, Ethiopia has oscillated with the trial of different economic models. In 2001, the regime adopted developmental state model along with ethnic federalism while abandoning liberalism. Taking these facts into account, this paper assesses the tension and compatibility between developmental state and ethnic federalism. The findings of this paper reveal that there are no problems associated with the developmental state in terms of rhetorical points of view. It can improve development if the governments strictly observe and implement the pillars that the developmental state needs to have. However, the marriage between developmental state and ethnic federalism incurs the possibility of the non-enforcement of the main pillars of the developmental state. The nature of the developmental state and the way Ethiopia’s federal system structured is incompatible, which I call such a relation the ‘matrimony of discordant’.