This work set out to study the relationship between foreign military intervention and preservation of national security of the intervening state. It was thus hinged on Uganda’s military intervention in South Sudan following the outbreak of the civil war in 2013. The study was cantered around 3specific objectives; assessing the national security concerns that motivated Uganda’s intervention in South Sudan in 2013; examining the national security threats that were mitigated in 2013 following Uganda’s intervention and assessing the challenges encountered by Uganda in preserving its national security following the intervention. The study concentrated on a time period of 2013-2018. The researcher used different data collection methods; the Focus Group Discussions (FGDs) and interviews. The data collection instruments used were Focus Group Discussion Guides and interview guides. The key respondents were the participants from the Ministry of Défense, a department charged with preservation of the country’s national interest. Other respondents were from the Ministry of foreign Affairs in charge of inter-state interactions and the public among others. The sample size was determined at the point of saturation because the study majorly adopted the qualitative research approach. Findings from the study indicated that a number of concerns such as economic interests; the life of Ugandans working in South Sudan and desire to maintain a status quo informed Uganda’s involvement in South Sudan. The study also found out that a number of security threats were mitigated with the intervention included; economic insecurity; prevention of a refugee and humanitarian crisis while the challenges to preservation of national security included; condemnation by the international community and the economic damages by the conflict on Uganda’s economic lifeline. The study recommended that, Uganda’s nationals must at all times be protected. However, the deployment should be having clear objectives, mandate and length to be spent to avoid allegations against Uganda as having ulterior motives in the neighbouring states. It also recommends that Uganda must be prepared to avert a humanitarian crisis any time especially within the immediate neighbouring countries because insecurity in the neighbourhood comes with a series of economic and socio-political as well as economic implications that affect her competitiveness. Lastly, the study recommended that there should always be clear arrangements xi between the regional players and international actors before the deployment is done in another state to avoid accusations

A dissertation submitted to the School of Social Sciences in partial fulfillment of the requirements for the award of the Master of Arts Degree in Security and Strategic Studies of Nkumba University.