Étaín or Édaín is a figure of Irish mythology, best known as the heroine of Tochmarc Étaíne, one of the oldest and richest stories of the Mythological Cycle. She also figures in the Middle Irish Togail Bruidne Dá Derga. T. F. O'Rahilly identified her as a sun goddess.

Tochmarc Étaíne, meaning "The Wooing of Étaín/Éadaoin", is an early text of the Irish Mythological Cycle, and also features characters from the Ulster Cycle and the Cycles of the Kings. It is partially preserved in the manuscript known as the Lebor na hUidre, and completely preserved in the Yellow Book of Lecan, written in language believed to date to the 8th or 9th century. It tells of the lives and loves of Étaín, a beautiful mortal woman of the Ulaid, and her involvement with Aengus and Midir of the Tuatha Dé Danann. It is frequently cited as a possible source text for the Middle English Sir Orfeo. Harvard professor Jeffrey Gantz describes the text as displaying the "poetic sense of law" in Irish legal society.