In Goidelic mythology, Deirdre was a beautiful heroine brought up by King Conchobar of Ulster. He planned on marrying her. She fell in love with Noise, his nephew; they fled to Scotland with his two brothers. Conchobar's messengers asked Noise and his brothers to return to Ireland. They did and he killed them. Deirdre died of grief.

There are two plays: William Butler Yeats's Deirdre (1907) and J.M. Synge's Deirdre of the Sorrows (1910).