This article analyses the development of civil-military relations in Ethiopia and how they are affected by politics, culture and ethnicity whilst drawing on compatibility theory. It explores a fundamental issue: to what extent does ethnic and cultural diversity influence civil-military relations in Ethiopia? The article begins with the hypothesis that the military's interests and political affiliations arise from their vision of the nation-state's interest, and may conflict with the attitudes of civil institutions, complicating the separation between civil and military institutional mandates. The article demonstrates how the social structure and distribution of tribes has had an impact on the reform processes of successive political systems in Ethiopia. Moreover, it concludes that consensus in civil-military relations and civilian control of government will continue in the future if slogans of centralization and citizenship are actualized through legal and democratic methods based on the principles of justice and equality in rights and duties among all constituents.