The study has focused on the role and motivations of the Bengali military officers in the Pakistan Army during the initial but critical phase of the Liberation War of 1971. Unlike the military in some other Third World Countries, at that point of time, the Bengali military officers made a move neither for grabbing political power nor for replacing a corrupt or inept regime but for establishing an independent state of Bangladesh. The concept of liberation war has been used in this study in the sense of an internal war between East and West Pakistan. The aims of this thesis are to explain why the Bengali military officers became actors in the Liberation War of 1971, how they were motivated for this war, when they took the crucial decision to revolt and declare independence of Bangladesh and how they proceeded till the formation of the Bangladesh Government-in-exile. The findings are also noteworthy. The Bengali political leaders prepared the people of East Pakistan for a revolutionary movement, but at the critical moment they faltered. As one of the dominant social forces in East Pakistan, the Bengali military officers watched from close quarters how the ethnically, linguistically and culturally different East Pakistanis were subjected to the discriminatory policies of the ruling elite in Pakistan which led to the wholesale alienation of the Bengalis. The 1970 general election worked as a catalyst to sharpen the east-west confrontation still further. The post-election negotiation between the political leaders of East and West Pakistan was used by the ruling elite of West Pakistan as a ploy to strengthen theirmilitary strength in East Pakistan, because they already decided to undertake a military solution to the political crisis, in fact for crushing the revolutionary movement by force. The Bengali military officers, who were deeply motivated by nationalistic aspirations, knew what was happening in the cantonments. That prompted them to take the critical decision of revolting from the Pakistan Army, declaring independence of Bangladesh and starting the Liberation War from 25 March 1971 when the political leaders were in disarray. Not only did they start the war but also continued the Liberation War on their own till 17 April 1971 when the Bangladesh Government-in-exile was formed to take it up. The Bengali military officers then accepted the command of the Bangladesh Government and ultimately came out victorious on 16 December 1971 through a grueling nine-month long Liberation War