William John Gruffydd (1916 – 21 April 2011), better known by his bardic name of Elerydd, was a Welsh Baptist minister and poet who served as Archdruid of the National Eisteddfod of Wales between 1984 and 1987. Like all Archdruids, Elerydd was himself the winner of a major prize at the National Eisteddfod, in his case the crown at the Pwllheli Eisteddfod in 1955 and at Cardiff in 1960.