Ethnic consideration has been comprehensively substantiated as a major trait in determining the political sustainability in Nigeria. Historically, the British overlord in 1914 saw forceful nuptials as a political necessity to safeguard and consolidate divergence ethnic pluralism, hypothesizing the dawn of ethnic consciousness in Nigerian political life. Ethnicity has been exploited as an instrument of oppression, therefore, becomes a time bomb lingering to explode in Nigerian political landscape. Military intervention in politics as an extra-legal and conspiratorial subjugation of government has been conventionally reprimanded as an aberration, despite their forbidden operational values in political engagements, various countries of the world such as Nigeria, France, Ghana, Uganda, Sudan, Somalia, Tanzania, Thailand, Iraq, Libya, Algeria, Afghanistan, Bangladesh, China, Azerbaijan, Cambodia, Russia, just to mention a few, have experienced military skyjacking of political power at one time or the other, therefore, this paper, discusses how ethnicity influences military takeover and civil war in Nigeria. Methodology espoused in carrying out this study was heavily derived from both secondary sources and insightful empirical observation of military trends in Nigeria. The study provides comprehensive critiques of ethnic nationalism in military governance which escorted the major ceaseless coup d’états and civil war in Nigeria. It is evident that major coordinated military coups have been splotched with ethnic gluttony which culminated into civil war, aimed at controlling the central political power, while thwarting socio-economic and political exertions in Nigeria. This paper therefore concludes that selective killings in military governance which journeyed through civil war exacerbated ethnic distrust among the major contending dominant groups (Hausa, Igbo and Yoruba) that ensuing protracted social unrest and general insecurity in Nigerian boisterous political odysse