Tylwyth Teg is the most usual term in Wales for the mythological creatures corresponding to the fairy folk of Welsh and Irish folklore Aos Sí. Other names for them include Bendith y Mamau, Gwyllion and Ellyllon.

A fairy is a type of mythical being or legendary creature, generally described as anthropomorphic, found in the folklore of multiple European cultures, a form of spirit, often with metaphysical, supernatural, or preternatural qualities.