Abstract: Under international law, official-capacity suits brought against a foreign state’s officers are treated as suits against the state itself and thus as subject to the state’s immunity, even in suits alleging human rights abuses. This immunity regime differs from the immunity regime that applies in the United States in suits brought against state and federal officials for violations of federal law. Despite the federal government’s sovereign immunity and the immunity of state governments under Eleventh Amendment jurisprudence, courts often allow suits against federal and state officers for their official actions. This essay attempts to explain why the immunity rules differ between the two regimes. We begin by showing that the differential treatment of foreign and domestic officer suits has deep roots in British and American common law. We then show that Congress has not acted to alter this common law backdrop, and we explain the significance of this fact. Finally, we discuss functional reasons for the long-time differential treatment of suits against domestic and foreign officials.