This chapter looks at reciprocity in the jurisdiction of international courts and tribunals, and the differences in the role reciprocity plays in inter-State dispute settlement, and in dispute settlement procedures that involve non-State entities such as individuals. It looks at the well-developed role that reciprocity plays in the jurisdiction of the International Court of Justice, before turning to the system of compulsory dispute settlement in the United Nations Convention on the Law of the Sea (UNCLOS). The chapter then analyzes three types of instance which concern individuals: the International Criminal Court; human rights courts and complaint mechanisms; and investment tribunals, specifically the issue of the extension of jurisdiction on the basis of an MFN clause.