Dionysius of Corinth was a Christian bishop active in the mid-to-late 2nd century CE, during the reign of the Roman emperor Marcus Aurelius. He served as the bishop of Corinth, a major city in Greece, at a time when the early Christian church was developing its institutional structures.

His significance comes from his role as a pastoral writer. He is known only through fragments of his correspondence preserved by the later church historian Eusebius. Dionysius wrote numerous letters to other Christian communities across the Roman world, including those in Sparta, Athens, Rome, and Nicomedia. These letters addressed practical issues like marriage and charity, as well as doctrinal matters. A major theme was combating early heresies, particularly the teachings of Marcion. His letter to the church in Rome thanks them for sending financial aid, which scholars see as an early example of the Roman see's growing administrative role.

None of Dionysius's letters survive in full; we have only excerpts quoted by Eusebius. According to modern scholars, this fragmentary correspondence is highly valuable. It provides a window into the networks that connected early Christian communities and shows how bishops like Dionysius exercised authority and promoted orthodox beliefs across great distances.