Owain ap Gruffydd may refer to:
- Owain Gwynedd (1100–1170) Prince of Gwynedd
- Owain Cyfeiliog (c. 1130 - 1197) Prince of part of Powys
- Owain Goch ap Gruffydd (died c. 1282) Brother of Llywelyn the Last of Gwynedd
- Owain Glyndŵr (1354–1416) Prince of Wales