Saint Hywel was a little-known saint of the Celtic Christian church in Wales during the 6th century. His exact dates of birth and death are unknown but he is thought to have been a disciple of Saint Teilo, and to have been a missionary in what is now West Wales.
A single church (at Llanhowell) is dedicated to Saint Hywel, and by tradition the land on which it was built was granted to Hywel by King Aercol (also Agricola, a sixth century king mentioned by Gildas), in gratitude for bringing order to Aercol's court.