Junius Bassus was a praetorian prefect of the Roman Empire from 318 to 331, during which time he also held the consulate. Several laws in the Codex Theodosianus are addressed to him. His son Junius Bassus Theotecnius was praefectus urbi, and his sarcophagus from 359 is one of the most decorative late antique sarcophagi adorned with two registers of Christian scenes.

He built the basilica of Junius Bassus on the Esquiline Hill in Rome, famous for its opus sectile decoration.