Legio III Gallica was a legion of the Imperial Roman army. The cognomen Gallica suggests that its earliest recruits came from veterans of the Gallic legions of Gaius Julius Caesar, a supposition supported by its emblem, a bull, a symbol associated with Caesar. The legion was based for most of its existence at Raphanea, Roman Syria, and was still active in Egypt in the early 4th century.

Roman Syria was an early Roman province annexed to the Roman Republic in 64 BC by Pompey in the Third Mithridatic War following the defeat of King of Armenia Tigranes the Great, who had become the protector of the Hellenistic kingdom of Syria.