This is a list of rulers of Brittany. In different epochs the rulers of Brittany were kings, princes, and dukes. The Breton ruler was sometimes elected, sometimes attained the position by conquest or intrigue, or by hereditary right. Hereditary dukes were sometimes a female ruler, carrying the title duchesse of Brittany. Its principal cities and regions were ruled by counts who often found themselves in conflict with the Breton ruler, or who became the Breton ruler.
During the declining years of the Roman Empire, the earliest Breton rulers in Gaul were styled "kings" of the small realms of Cornouaille and Domnonée. Some such kings may have had a form of hegemony over all of the Brythonic populations in the Armorican peninsula, and Riothamus is called King of the Britons by the chronicler Jordanes. However, there are no certain rulers of the whole of Brittany, which was divided into the fiefdoms of local counts.
