Eutharic Cilliga (Latin: Flavius Eutharicus Cillica) was an Ostrogothic prince from Iberia (modern-day Spain) who, during the early 6th century, served as Roman Consul and "son in arms" (filius per arma) alongside the Byzantine emperor Justin I. He was the son-in-law and presumptive heir of the Ostrogoth king Theoderic the Great but died in AD 522 at the age of 42 before he could inherit Theoderic's title. Theoderic claimed that Eutharic was a descendant of the Gothic royal house of Amali and it was intended that his marriage to Theoderic's daughter Amalasuintha would unite the Gothic kingdoms, establish Theoderic's dynasty and further strengthen the Gothic hold over Italy.
During his year of consulship in 519 relations with the East Roman Empire flourished and the Acacian schism between the Eastern and Western Christian churches was ended. Whilst Eutharic was nominally a statesman, politician and soldier of the Roman Empire, he was also an Arian, whose views clashed with the Catholic majority; as consul enforcing Theoderic's tolerant policy towards the Jewish people, he incurred resentment from the local Catholics, whose traditions were less than tolerant. Following disturbances in Ravenna, where Catholics burnt down a number of synagogues, Eutharic's siding with the Jewish people of Ravenna was reported with resentment in a fragmentary contemporary chronicle.