Muhammad, BelloHussaini, Hassan Tukur2023-12-112023-12-112015-08-12Hussaini, H.T. & Muhammed, B. (2015) WEST AFRICA SUB-REGIONAL CRISES AND THE NIGERIAN ARMY PEACE SUPPORT OPERATION IN SIERRA-LEONEhttps://keffi.nsuk.edu.ng/handle/20.500.14448/2509The end of cold war between the super powers shifted conflicts based on ideologies to regional and local conflicts which were mostly ethnic; sectional, economic, environmental and religious based. More worrisome is the changing nature of conflicts from inter-state to intra-state. This paper examines Nigeria army (NA) participation in Peace Support Operation (PSO) in Africa with sierra-Leone as a case study. The study is necessary because despite Nigeria's experience in Peace Support Operations (PSO), the NA is for long bedevilled with problems of preparation, planning, training, logistics and the conduct of the PSO. The paper will determine the extent of Nigeria involvement in PSO and its implication on the nation's economy. The objectives of the study include; examining the relationship between Army and PSO, examining the roles played by the NA in the PSO in Sierra-Leone, identify the challenges encountered and proffer strategies to enhance NA's participation in future PSOs. Data for the study were collected from secondary sources. The major findings were the NA had ambiguous mandates; poor logistics, poor training and lack of adequate planning and preparations adversely affected its performance. The study recommended that to enhance future NA performance there is the need to ensure capacity building, defined policy on PSO, ' coordination and cooperation with the UN. Others are need for a national policy and PSO doctrine, provision of adequate intelligence gathering before troop's deployment to mission area and adequate funding and logistics. Keywords: Peace, Peace Support Operation, Peacemaking, Peace Enforcement & Peace Building.enPeace, Peace Support Operation, Peacemaking, Peace Enforcement & Peace Building.Article