This article takes up the question of perjury and the oath in Derrida’s later work. It proposes that Derrida’s reflections on such theological concepts need to be understood, less as part of a "religious turn," and more in the context of political and juridical theology, or the manner in which modern politics and law are haunted by theology. It shows how, for Derrida, every social relation is structured by an oath, or an implied promise to tell the truth, and a perjury, or a betrayal of that promise. It develops this argument through a consideration of Derrida’s engagements with Levinas and de Man.