In demonology Barbas is a Great President of Hell and governs thirty-six legions of demons. He answers truly on hidden or secret things, causes and heals diseases, teaches mechanical arts, and changes men into other shapes.

He is depicted as a great lion that under the conjurer's request changes shape into a man.

The name Barbas seems to come from Latin 'barba', beard, hellebore (a plant used in witchcraft, especially to invoke demons), and also a male name.

Other spelling: Marbas.

See also The Lesser Key of Solomon, Ars Goetia.