The Gothic War between the East Roman (Byzantine) Empire during the reign of Emperor Justinian I and the Ostrogothic Kingdom of Italy took place from 535 until 554 in the Italian peninsula, Dalmatia, Sardinia, Sicily and Corsica. It was one of the last of the many Gothic Wars with the Roman Empire. The war had its roots in the ambition of the East Roman Emperor Justinian I to recover the provinces of the former Western Roman Empire, which the Romans had lost to invading barbarian tribes in the previous century (the Migration Period).

The war followed the East Roman reconquest of the province of Africa from the Vandals. Historians commonly divide the war into two phases:

From 535 to 540: ending with the fall of the Ostrogothic capital Ravenna and the apparent reconquest of Italy by the Byzantines.

From 540/541 to 553: a Gothic revival under Totila, suppressed only after a long struggle by the Byzantine general Narses, who also repelled an invasion in 554 by the Franks and Alamanni.In 554 Justinian promulgated the Pragmatic sanction which prescribed Italy's new government. Several cities in northern Italy held out against the East Romans until 562. By the end of the war Italy had been devastated and depopulated. The East Romans found themselves incapable of resisting an invasion by the Lombards in 568, which resulted in Constantinople permanently losing control over large parts of the Italian peninsula.