Abstract Following the discussion of the options for invoking the International Criminal Court (ICC) or creating a new international institution to address the crimes in Syria, chapter 7 explores the potential for domestic courts to fill this impunity gap. Principles of complementarity, including the incorporation of international crimes into the world’s domestic penal codes, have contributed to the emergence of more empowered and aggressive domestic courts when it comes to the prosecution of grave crimes of international concern. The chapter demonstrates the way in which classic principles of domestic criminal jurisdiction—territoriality, effects, nationality (active and passive), protective, and universal jurisdiction—could all be, and are all being, activated to address the presence of perpetrators and victims found outside the Syrian battlespace. This chapter offers a taxonomy of the criminal cases proceeding to date in domestic courts around the world, some involving the state’s own nationals, some involving perpetrators found within the territorial state, and some proceeding in various ways while the defendant is still in absentia. This chapter offers explanations for the developments afoot within states—and the European Union in particular—that have enabled domestic courts to emerge as the most promising venue for justice. While compiling a number of overarching observations about this collection of cases, the chapter also acknowledges their inherent limitations, in general and when it comes to Syria in particular, as well as sources of resistance to the expansion of these forms of extraterritorial jurisdiction.