Brân the Blessed is a giant and king of Britain in Welsh mythology. He appears in several of the Welsh Triads, but his most significant role is in the Second Branch of the Mabinogi, Branwen ferch Llŷr. He is a son of Llŷr and Penarddun, and the brother of Brânwen, Manawydan, Nisien and Efnysien. The name "Brân" in Welsh is usually translated as crow or raven.

Welsh mythology consists of both folk traditions developed in Wales, and traditions developed by the Celtic Britons elsewhere before the end of the first millennium. As in most of the predominantly oral societies Celtic mythology and history were recorded orally by specialists such as druids. This oral record has been lost or altered as a result of outside contact and invasion over the years. Much of this altered mythology and history is preserved in medieval Welsh manuscripts, which include the Red Book of Hergest, the White Book of Rhydderch, the Book of Aneirin and the Book of Taliesin. Other works connected to Welsh mythology include the ninth-century Latin historical compilation Historia Brittonum and Geoffrey of Monmouth's twelfth-century Latin chronicle Historia Regum Britanniae, as well as later folklore, such as the materials collected in The Welsh Fairy Book by William Jenkyn Thomas (1908).