This chapter examines the intersection between immigration policy, which is often regarded as a domestic matter, and international relations. The US government must negotiate with other nations concerning key aspects of immigration including the citizenship status of people who have moved and the protections and rights due to migrants of various nationalities when they travel in areas governed by other sovereign nations. Because differential rights of entry signal friendships and respect between nations, or disdain and hostility for other countries and their peoples, unacceptably discriminatory restrictions on mobility and residence can damage international friendships. A sovereign nation’s capacities to enforce its immigration restrictions and secure rights of safe travel for its citizens abroad also signal its international standing.