Ralph ap Cadwaladr (c.1150-c.1220) or was the fourth son of Cadwaladr ap Gruffydd the brother of Owain Gwynedd the king of Gwynedd and overlord of all Wales. He probably spent his whole life in exile in England. It is not yet known for certain if he had any children but it is said that some people with the surnames "Waley" and "Walsh" are descendants of him and his brother Rhicert.