William John Gruffydd (born Feb. 14, 1881, Bethel, Caernarvonshire, Wales—died Sept. 29, 1954, Caernarvon) was a Welsh-language poet and scholar whose works represented first a rebellion against Victorian standards of morality and literature and later a longing for the society he knew as a youth.
Educated at the University of Oxford, Gruffydd was appointed professor of Celtic at University College, Cardiff, Wales, a position he held until his retirement in 1946. He edited the Welsh quarterly review Y llenor (“The Literary Man”) from its inception in 1922 until 1951, when it was discontinued.
His earliest work, with R. Silyn Roberts, the book of poems Telynegion (1900; “Lyrics”), naturalized the romantic lyric in Wales. Other works include Caneuon a cherddi (1906; “Songs and Poems”), Llenyddiaeth Cymru o 1450 hyd 1600 (1922; “History of Welsh Literature, 1450–1600”), Ynys yr hud (1923; “The Enchanted Island”), Caniadau (1932; “Poems”), and Hen atgofion (1936; “Old Memories”).