Since 1991, NATO has played a prominent role in peacekeeping and peace enforcement in the Balkans and Afghanistan. Despite NATO’s role in peacekeeping, there is little literature that compares the efficacy of NATO and UN peace enforcement operations. However, some existing literature suggests that NATO peacekeepers should be able to use coercion more effectively than UN peacekeepers, whereas UN peacekeepers should be to use inducement and persuasion more effectively than NATO peacekeepers. This paper uses a small-N most similar case design and the process tracing method to investigate how effective NATO peace enforcement is at reducing war intensity compared to UN peace enforcement. This paper also studies how NATO and UN peacekeepers use coercion, inducement and persuasion to reduce war intensity during peace enforcement operations. Based on a case study comparing the NATO IFOR operation in Bosnia to the UN UNOSOM II operation Somalia, this paper finds that NATO peace enforcement operations reduce war intensity to a greater degree than UN peace enforcement operations. Furthermore, this paper also finds that NATO peacekeepers use coercion, inducement and persuasion more effectively than UN peacekeepers.