Gaius Julius Antiochus Epiphanes Philopappos or Philopappus, was a Prince of the Kingdom of Commagene who lived in the Roman Empire during the 1st century and 2nd century. He was one of the most prominent Greeks in the Empire.

Commagene was an ancient Greco-Iranian kingdom ruled by a Hellenized branch of the Iranian Orontid dynasty that had ruled over Armenia. The kingdom was located in and around the ancient city of Samosata, which served as its capital. The Iron Age name of Samosata, Kummuh, probably gives its name to Commagene.