Etain (also Étain, Étáin) can refer to:

• Étaín, a character from Irish mythology
• the fairy princess in Rutland Boughton's opera The Immortal Hour
• the fairy princess in the play The Immortal Hour (play)
• Étain, France, a commune in the Meuse département in France
• Étain, the French word for tin or pewter
• Etain, the name of a fictional character from the Pict province of Rome, from the film Centurion

Étaín or Édaín (Modern Irish spelling: Éadaoin) is a figure of Irish mythology, best known as the heroine of Tochmarc Étaíne (The Wooing Of Étaín), one of the oldest and richest stories of the Mythological Cycle. She also figures in the Middle Irish Togail Bruidne Dá Derga (The Destruction of Da Derga's Hostel). T. F. O'Rahilly identified her as a sun goddess.