Goronwy ab Ednyfed (c. 1210 – 17 October 1268) was seneschal to Llywelyn ap Gruffudd, king of Gwynedd.
Goronwy continued in this role for the following ten years, during which time he was involved in a variety of negotiations with the Marcher Lords, with Richard, the Bishop of Bangor, and with several other Welsh princes.
Goronwy led Llywelyn's troops as far south as Gwent to combat the Marcher Lords in February 1263.
Goronwy died on St Luke's Eve, 17 October 1268, according to the Brut y Tywysogion: "The following year Goronw son of Ednyfed, seneschal to the prince, died on the eve of St Luke the Evangelist, a man excellent in arms, generous with gifts, wise in counsel, loyal in deeds, and pleasant in words."
By founding the Tudor family of Penmynydd,[4] Goronwy began a lineage which came to include kings and queens of England.