In Goedelic mythology, Macha was one of the three aspects of the Morrigan. She fed on the heads of her enemies. With Anann and Badb, she formed a triumvirate of war goddesses; specifically, Macha was often said to have cured the wounded. She is said to have been the queen of Ulster, the capital of which, Emain Macha, was named after her. With the other Morrigan, Badb, Nemhain and Fea, she was part of a group of Irish war goddesses. She and the other Morrigan helped the Tuatha De Dannan find against the Fir Bolgs.

She may have been related to the British Morgan and the continental Celtic Epona.