William Williams (pen name "Caledfryn" or "Gwilym Caledfryn") (6 February 1801 – 23 March 1869) was a Welsh Congregational minister, poet and literary critic born at Bryn y Ffynnon, Denbigh.

He studied at Rotherham College before becoming ordained as a minister with the Independents in 1829.

In 1851 he published Grammadeg Cymreig, an important book of Welsh grammar.

[2] He published Cyfarwyddiadur i Ddarllen ac Ysgrifennu Cymraeg ("A Guide to reading and writing Welsh" in 1821; Grawn Awen, a volume of verse in 1826; and Drych Barddonol neu Draethawd ar Farddoniaeth (an essay on Poetry) in 1839.

[1] He spent the last days of his life in South Wales as minister at Groeswen Independent Chapel, near Cardiff in Glamorgan.