Glewlwyd Gafaelfawr ("Brave Grey Mighty Grasp") is a hero, warrior, and porter in tradition and Arthurian mythology, in which he appears as a knight in Arthur's retinue and chief gatekeeper of his court. He is one of the earliest characters to be associated with Arthur and appears in a number of texts, including Culhwch ac Olwen, Geraint fab Erbin, Iarlles y Ffynnon, Pa Gur yv y Porthur and the Welsh Triads.