The study investigates the intricate dynamics of civil-military relations in Nigeria from 1966 to 1999, a period marked by significant political turbulence and military interventions. Employing an interdisciplinary approach, it examines fundamental concepts and theories underpinning civil-military relations, tracing their evolution within the Nigerian context. Through a comprehensive analysis of historical phases, including the First and Second Republics, military regimes led by figures such as Murtala/Obasanjo, Babangida, Abacha, and Abubakar, the study elucidates the shifting power dynamics between civilian and military actors. Emphasizing the struggle for authority and legitimacy, the research explores how the military sought to entrench its influence while civilians challenged its dominance within the political landscape. By contextualizing historical events and socio-economic factors, the study provides valuable insights into the complexities of governance and security in post-colonial Nigeria