Legio IV Scythica was a Roman legion levied by Marcus Antonius around 42 BC, for his campaign against the Parthian empire, hence the cognomen Parthica. The legion was still active in Syria province in the early 5th century. The legion's symbol was a capricorn.

In its first years, the whereabouts of IV Scythica are uncertain, although it is probable that they took part on Antonius' campaign against the Parthians. The name suggests that they fought against the Scythians. After the battle of Actium and Antonius' suicide, Octavian transferred the IV Scythica to the Danube province of Moesia. The legion is reported to take part in civilian tasks, such as the building and keeping of roads. In his youth, future emperor Vespasian served in this legion.

Between 58 and 60 AD, IV Scythica was stationed in the East, fighting in the war for Armenia with other legions such as Legio III Gallica, under Gnaeus Domitius Corbulo's command. In 62, the IV Scythica and Legio XII Fulminata were defeated by the Parthians and forced to surrender. The legions were covered with shame and removed from the war theatre to Zeugma. This city would be the base camp of IV Scythica for the next century.

In the year of the four emperors (69 AD), the legion, like the rest of the Eastern army, sided with Vespasian from day one. Despite the demonstrated loyalty, the IV Scythica was not involved in actual fighting because they were not considered a high quality legion. This has to do with another suffered defeat years earlier in the Jewish rebellion. In the 2nd century they participated in the control of another Jewish rebellion, this time with more success.

The IV Scythica participated in all campaigns of the 2nd century against the Parthian Empire. Between 181 and 183 AD, the legions commander was future emperor Lucius Septimius Severus. The legion disappears from the sources after 219, when their commander rebelled against Heliogabalus. However, in the early 5th century they were still in Syria.

See also: List of Roman legions

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