Marcus Julius Gessius Bassianus (flourished 3rd century) was a Magister (master) in the Arval Brethren during the reign of Roman emperor Caracalla who ruled from 212 until 217.
Bassianus seems to be linked to the Julii and the Bassiani. From his name, could point to him as a possible son of the Syrian Roman nobles Marcus Julius Gessius Marcianus and Julia Avita Mamaea, being a possible elder brother of Roman emperor Alexander Severus and his sister, Theoclia. If this is correct, Bassianus was a relation to the Royal family of Emesa and the Severan dynasty of the Roman Empire.
Bassianus was not a known Priest of the cult of Elagabalus. Although he was a Roman Priest, was unable to attend the ceremonies of the Arval Brethren in Rome, probably due to Bassianus being based in the East.