Eunapius was a Greek sophist and historian of the 4th century.

He was born at Sardis, AD 347. In his native city he studied under his relative, the sophist Chrysanthius, and while still a youth went to Athens, where he became a favourite pupil of Proaeresius the rhetorician. He possessed considerable knowledge of medicine. In his later years he seems to have lived at Athens, teaching rhetoric. Initiated into the Eleusinian Mysteries, he was admitted into the college of the Eumolpidae and became hierophant. There is evidence that he was still living in the reign of the younger Theodosius.

Eunapius was the author of two works, one written in 405 entitled Lives of the Sophists, and the other consisting of a continuation of the history of Dexippus. The former work is still extant; of the latter only excerpts remain, but the facts are largely incorporated in the work of Zosimus. It embraced the history of events from AD 270-404.

The Lives of the Sophists, a collection of the biographies of twenty-three older and contemporary philosophers and sophists of the author, is valuable as the only source for the history of the neoplatonism of that period. The style of both works is marked by a spirit of bitter hostility to Christianity. Photius had before him a "new edition" of the history in which the passages most offensive to Christians were omitted.

Edition of the Lives by JF Boissonade (1822), with notes by D Wyttenbach; history fragments in CW Müller , Fragmenta Hist. Graecorum, iv.; V Cousin, Fragments philosophiques (1865); translation: W. C. Wright in the Loeb Classical Library edition of Philostratus Lives of the Sophists (1921).