This dissertation investigates the use of sarcasm in the undisputed letters of Paul. A methodologically rigorous treatment of this subject can make an important contribution to Pauline studies, as determining whether a given passage is meant sincerely or sarcastically has a considerable impact on interpretation. Observing Paul’s use of sarcasm can also contribute to the study of Pauline rhetoric, elucidating a facet of Paul’s argumentative strategy and providing a novel angle from which to assess the ways he negotiates his relationships with different early-Christian congregations. To break ground on the study of ancient sarcasm before turning to Paul, Part 1 of this dissertation explores three central questions: What is sarcasm? How is sarcasm expressed? And what does sarcasm do? To answer the first question, we review ancient and modern scholarship on irony and sarcasm to construct a working definition of sarcasm. The following two chapters address the latter two questions by treating the issues of sarcasm recognition in ancient Greek and sarcasm’s rhetorical functions through a series of case studies: the first on the Septuagint with special reference to the book of Job and the prophets, and the second on an eclectic selection of ancient Greek texts with special reference to Lucian of Samosata. Part 2 focuses on the identification and exegesis of sarcasm in Paul. The relationship between Galatians’s opening (1:6), irony, and ways of expressing rebuke in ancient letters will feature in our chapter on Galatians. Diatribe will play a major role in our discussion of Romans. In order to clarify the presence of sarcasm throughout the letter, I will offer a revised conception of authorial voice in dialogical passages, which can nuance previous scholarship on diatribe. First Corinthians provides the opportunity to address the presence of sarcasm in the letter’s “Corinthian slogans.” Work on Second Corinthians will focus on the relationship between sarcasm and asteismos, a self-deprecating form of irony that, in Paul, occurs significantly only in 2 Cor 10–13.