"In the 20th century, states have increasingly sought to apply their laws to situations and persons beyond their borders. They typically did so to protect their own interests from harm spilling over their borders. Recently, however, states appear to be giving their laws ‘extraterritorial’ application to protect global interests, not only when prosecuting international criminals, but also by enacting emissions trading schemes to tackle global warming, by taking sanctions against foreign vessels involved in illegal fishing on the high seas docking in their port, and by fighting foreign corrupt practices with a view to furthering good governance in developing countries. Thus, it appears that a novel principle of jurisdiction is crystallizing that protects global interests through unilateral application of domestic (or regional) law. It is the aim of this research to study this development in-depth, and to examine in particular whether, and under what circumstances, international law countenances such an exercise of unilateral jurisdiction that is aimed at the protection of global interests.The project consists of two pillars. Pillar 1 studies three cases of states or regional organizations unilaterally applying their own laws to (partly) foreign situations considered as threatening global interests: (a) the exercise of unilateral jurisdiction aimed at mitigating climate change; (b) the exercise of port state jurisdiction aimed at protecting sustainable fishing and biological diversity on the high seas; (c) the exercise of unilateral jurisdiction to tackle foreign corruption practices. Pillar 2 is synthetic in nature, and assesses whether, and to what extent, general rules of jurisdiction and jurisdictional restraint concerning the protection of global interests are developing across various fields, including but not limited to the fields studied in Pillar 1."