Procopius Anthemius (Ancient Greek: Προκόπιος Ανθέμιος, romanized: Prokópios Anthémios; died 11 July 472) was the Western Roman emperor from 467 to 472. Born in the Eastern Roman Empire, Anthemius quickly worked his way up the ranks. He married into the Theodosian dynasty through Marcia Euphemia, daughter of Eastern emperor Marcian. He soon received a significant number of promotions to various posts, and was presumed to be Marcian's planned successor. However, Marcian's sudden death in 457, together with that of Western emperor Avitus, left the imperial succession in the hands of Aspar. He instead appointed Leo, a low-ranking officer, to the Eastern throne, probably out of fear that Anthemius would be too independent. Eventually, this same Leo designated Anthemius as Western emperor in 467, following a two-year interregnum that started in November 465.

Anthemius attempted to solve the two primary military challenges facing the remains of the Western Roman Empire: the resurgent Visigoths, under Euric, whose domain straddled the Pyrenees; and the unvanquished Vandals, under Geiseric, in undisputed control of North Africa. Anthemius's insistence on ruling independently placed him into direct conflict with the Gothic general Ricimer. Previously the real power behind the throne, Ricimer found that Anthemius's reign threatened his own interests. This eventually escalated into open warfare between the two, with the result that Anthemius lost not only his throne, but also his head, in 472.

Anthemius belonged to a noble family, the Procopii, which gave several high officers, both civil and military, to the Eastern Roman Empire. His maternal grandfather was Anthemius, praetorian prefect of the East (404–415) and Roman consul in 405. His father was Procopius, magister militum per Orientem from 422 to 424, who descended from Procopius, a cousin of Emperor Julian and a usurper against the Eastern emperor Valens (r. 365–366).

Born in Constantinople, he went to Alexandria to study in the school of the Neoplatonic philosopher Proclus; among his fellow students, there were Marcellinus (magister militum and governor of Illyricum), Flavius Illustrius Pusaeus (Praetorian prefect of the East and Consul in 467), Messius Phoebus Severus (Consul in 470 and praefectus urbi), and Pamprepius (pagan poet).

In 453, he married Marcia Euphemia, daughter of the Eastern emperor Marcian (450–457); after the marriage, he was elevated to the rank of comes and sent to the Danubian frontier with the task of rebuilding the border defences, neglected after Attila's death in 453. In 454, he was recalled to Constantinople, where he received the title of patricius in 454 or 455 and became one of the two magistri militum or magister utriusque militiae of the East. In 455, he received the honour of holding the consulate with the Western emperor Valentinian III as a colleague.

This succession of honourable events – the wedding with Marcian's daughter; a promotion to an important military rank, but with administrative rather than military tasks; the prestigious rank of patricius and the highest military position; the consulate held with an Emperor as a colleague – suggests that Marcian had selected Anthemius as a possible candidate for the Eastern or Western throne. This hypothesis is strengthened by the fact that Anthemius' prestige misled the 6th-century historian John Malalas to state that Marcian had designated Anthemius as Western Emperor after Avitus.

In October 456, the Western emperor Avitus was deposed; Marcian probably considered Anthemius as his successor, but the Eastern emperor died in January 457 before choosing his colleague. Therefore, both empires had no emperor, and the power was in the hands of the Western generals, Ricimer and Majorian, and the Eastern Magister militum, the Alan Aspar. As Aspar could not sit on the throne because of his barbarian origin, he opposed Anthemius, whose prestige would have made him independent, and chose a low-ranking military officer, Leo; in the West, as his barbarian origin barred Ricimer from the throne, it was Majorian who received the purple.

Anthemius stayed in service under the new emperor; as magister militum, his task was to defend the Empire from the barbarian populations pressing on its border. Around 460, he defeated the Ostrogoths of Valamir in Illyricum. During the winter of 466/467, he defeated a group of Huns, led by Hormidac, who had crossed the frozen Danube and pillaged Dacia. The raiders had conquered Serdica, and Anthemius besieged the city until the starved Huns decided to accept open battle; despite the treachery of his cavalry commander (a Hun), Anthemius led his infantry to victory, and when Hormidac offered surrender Anthemius asked for the deserter to be given to him.