Gwenllian of Wales or Gwenllian ferch Llywelyn was the daughter of Llywelyn ap Gruffudd, the last native Prince of Wales. Gwenllian is sometimes confused with Gwenllian ferch Gruffudd, who lived two centuries earlier.

Llywelyn ap Gruffudd, Llywelyn II, also known as Llywelyn the Last, was the prince of Gwynedd, and later was recognised as the prince of Wales from 1258 until his death at Cilmeri in 1282. Llywelyn was the son of Gruffydd ap Llywelyn Fawr and grandson of Llywelyn the Great, and he was one of the last native and independent princes of Wales before its conquest by Edward I of England and English rule in Wales that followed, until Owain Glyndŵr held the title during the Welsh Revolt of 1400–1415.