Saint-Gildas () is a commune in the Côtes-d'Armor department of Brittany in northwestern France.
Inhabitants of Saint-Gildas are called Gildasiens and Gildasiennes in French.
Breton legend connects Gildas with Brittany. The first book by the Irish writer Julia Kavanagh, Saint-Gildas, or, The Three Paths (1847) is largely set in the village in the eighteenth century.