In demonology Glasya-Labolas is a mighty President (and Earl to other authors) of Hell who commands thirty-six legions of demons. He teaches all arts (and sciences to some authors), just in an instant according to some demonologists. He is the author and captain of manslaughter and bloodshed, tells all things past and to come, gains the minds and love of friends and foes causing love among them if desired, incites homicides and can make a man invisible.

He is depicted as a dog with the wings of a griffin.

Other spellings: Caacrinolaas, Caassimolar, Classyalabolas, Glassia-labolis, Glasya Labolas.

See also The Lesser Key of Solomon, Ars Goetia.