Ondine is a ballet in three acts created by the choreographer Sir Frederick Ashton and composer Hans Werner Henze. Ashton originally produced Ondine for the Royal Ballet in 1958, with Henze commissioned to produce the original score, published as Undine, which has since been restaged by other choreographers. The ballet was adapted from a novella titled Undine by Friedrich de la Motte Fouqué and it tells the tale of a water nymph who is the object of desire of a young prince named Palemon. The première of the ballet took place at the Royal Opera House, London, on 27 October 1958, with the composer as guest conductor. The first major revival of this Ashton/Henze production took place in 1988.

Sir Frederick William Mallandaine Ashton was a British ballet dancer and choreographer. He also worked as a director and choreographer in opera, film and revue.