Fourth Legion

4th Legion may refer to:


 * Legio IV Macedonica founded in 48 BC
 * Legio IV Scythica founded c. 42 BC by the general Mark Antony
 * Legio IV Flavia Felix founded in AD 70 by the emperor Vespasian from the ashes of the Legio IV Macedonica
 * Legio IV Martia
 * Legio IV Italica founded in AD 231 by emperor Alexander Severus