Eparchius Avitus (c. 385 – after 17 October 456 or in 457) is Western Roman Emperor from July 8 or 9, 455 to October 17, 456.

A Gallo-Roman aristocrat, he is a senator and a high-ranking officer both in the civil and military administration, as well as Bishop of Piacenza.

A representative of a Gallic-Roman aristocracy, he opposes the reduction of the Western Roman Empire to Italy alone, both politically and from the administrative point of view.

For this reason, as Emperor he introduces several Gallic senators in the Imperial administration; this policy, however, is opposed by both the Senatorial aristocracy and by the people of Rome, which have suffered because of the Vandalic sack of the city in 455.

Avitus has a good relationship with the Visigoths, in particular with their king Theodoric II, who is a friend of his and who acclaims Avitus Emperor, but the possibility of a strong and useful alliance between Visigoths and Romans ends when Theodoric invaded Roman Hispania and then refuses to help Avitus against the rebel Roman generals who had deposed him.