This chapter discusses the establishment of the Special Court for Sierra Leone as the first treaty-based international criminal tribunal between the United Nations and one of its Member States. Although the Special Court’s legal framework benefitted from the precedents of the International Criminal Tribunals for Former Yugoslavia and Rwanda, the process of the establishment of Special Court posed new challenges for the international community. First, the chapter assesses how the international community and the government of Sierra Leone had competing visions for the Special Court. While President Kabbah urged the UN to create a full ad-hoc international tribunal similar to the one for Rwanda, the Security Council had plans to create the court using a new more consensual treaty approach in an attempt to cut costs. Second, it discusses the influence of Security Council permanent members, especially the United States and the United Kingdom, in shaping the ultimate design of the treaty-based court as a means to maintain some United Nations authority while supporting domestic prosecutions in the country where the crimes were committed. Finally, the chapter examines the final signed treaty and the six major institutional features evident within the Court’s founding documents.