Since the UN’s inception in 1945, one of its main goals has been to solve conflicts around the world through peacekeeping. The quality of these peacekeeping operations has varied as some of them have been successful in achieving peace and some have been a failure as the UN were not able to solve the conflict. Two of these peacekeeping operations are the United Nations Mission in Sierra Leone (UNMASIL), where the conflict was solved and the United Nations Mission in South Sudan (UNMISS), where the conflict is still ongoing after a decade of UN peacekeeping. 

This thesis will examine how well the UN has acted in these countries with the help of Severine Autesserre’s theory on dominant peace culture. The result shows that the UN managed to assist in building a dominant peace culture in Sierra Leone and that it was key in order to solve the conflict between the government and the rebels. The opposite could be said about South Sudan as the UN has failed to build a dominant peacebuilding culture in South Sudan as the armed conflict has forced the UN to step back. The result shows that UNMISS have a lot to learn from UNAMSIL as they managed to turn the conflict around when it looked the worst, which means that there is still hope for UNMISS to do the same if they rethink their strategy.