The Pausanias and Xerxes Letters is a pseudepigraphical collection of epistles attributed to the Spartan regent Pausanias and the Persian King Xerxes I. It purports to document Pausanias's offer to betray Greece after the Persian Wars, an allegation rooted in the historical tradition reported by Thucydides. Modern scholarship regards the collection as a later rhetorical exercise or literary fabrication, likely composed well after the 5th century BCE events it describes.

The sole extant work is the Pausanias and Xerxes Letters, a collection preserved within the corpus of Greek epistolography. The letters are significant as an artifact of ancient pseudepigraphical practice, exemplifying the Hellenistic and later tradition of composing invented correspondence between historical figures. They reflect later antiquity's rhetorical engagement with Classical history, reimagining the narrative of Pausanias's alleged Medism and themes of betrayal from the Persian Wars.