Rhys Gethin (died in 1405) was a key figure in the revolt of Owain Glyndŵr. He was his standard bearer and a leading general. His name means "swarthy Rhys".Little is known of his life. He had a brother, Hywel Coetmor, who also played a significant role in the rising. It is claimed that they were the grandsons of an illegitimate son of Dafydd ap Gruffydd.He took part in the crucial Welsh victory at the Battle of Bryn Glas in 1402.