Owain Gwynedd ap Gruffydd (Middle Welsh: Owain Gwyned; c. 1100 – 28 November 1170) is King of Gwynedd from 1137 until his death in 1170, and the first to be known as Prince of Wales.

He is considered to be the most successful of all the north Welsh princes prior to his grandson, Llywelyn the Great.

He is known as Owain Gwynedd to distinguish him from another contemporary Owain ap Gruffydd, ruler of part of Powys who is known as Owain Cyfeiliog.

Owain Gwynedd is a member of the House of Aberffraw, a descendant of the senior branch from Rhodri Mawr.