Legio VIII Augusta was a Roman legion created by Julius Caesar and continuing in service to Rome for at least 400 years thereafter.

It was levied by Caesar in 59 BC, or possibly earlier. Between 58 and 49 BC they fought in the Gallic wars under Caesar. In 49 Legio VIII accompanied Caesar across the Rubicon into Italy, at the very beginning of the civil war between Caesar and Pompey, and at the Battle of Pharsalus. The legion was also present in Egypt, when Caesar captured Egypt for Cleopatra. In 46 BC the legion took part in the Battle of Thapsus (modern Tunisia), shortly before their disbandment.

In 44 BC, Augustus reconstituted the legion which had helped him attain the control of the Empire. This loyalty gave the legion the cognomen Augusta. Legio VIII took part in the Roman invasion of Britain.

In 69 AD, the Year of the Four Emperors, following the suicide of Nero, the legion took the part of Vitellius, one of the defeated emperors. After that they were moved to the Rhine frontier, where they stayed for almost the entire remainder of their history. The legion also fought in Parthia with Septimius Severus (who ruled from 193 until 211) and with his successors.

Records indicate that they were still active during the first years of the 4th century at the Rhine frontier. This means that the history of the legion covers more than 400 years of almost continuous service.

See also: List of Roman legions