Flavius Belisarius (Greek: Βελισάριος, c. 500[2] – 565 AD) was a general of the Byzantine Empire. He was instrumental to Emperor Justinian's ambitious project of reconquering much of the Mediterranean territory of the former Western Roman Empire, which had been lost less than a century previously.

One of the defining features of Belisarius' career was his success despite varying levels of support from Justinian. His name is frequently given as one of the so-called "Last of the Romans".