Marcus Sedatius Severianus (105–161 or 162) was a Roman senator, suffect consul, and general during the 2nd century AD, originally from Gaul. Severianus was a provincial governor and later a provincial consul. The peak of his career was as suffect consul for the "nundinium" of July–September 153 as the colleague of Publius Septimius Aper. He was governor of Cappadocia at the start of the Roman war with Parthia, during which he was convinced by the untrustworthy oracle to invade Armenia in 161. Sedatius committed suicide while under siege in the Armenian city of Elegeia, on the upper Euphrates. The legion he led was wiped out shortly after. He was replaced as governor of Cappadocia by Marcus Statius Priscus.