Orfeo ed Euridice is an opera composed by Christoph Willibald Gluck, based on the myth of Orpheus and set to a libretto by Ranieri de' Calzabigi. It belongs to the genre of the azione teatrale, meaning an opera on a mythological subject with choruses and dancing. The piece was first performed at the Burgtheater in Vienna on 5 October 1762, in the presence of Empress Maria Theresa. Orfeo ed Euridice is the first of Gluck's "reform" operas, in which he attempted to replace the abstruse plots and overly complex music of opera seria with a "noble simplicity" in both the music and the drama.

Opera is a form of theatre in which music is a fundamental component and dramatic roles are taken by singers. Such a "work" is typically a collaboration between a composer and a librettist and incorporates a number of the performing arts, such as acting, scenery, costume, and sometimes dance or ballet. The performance is typically given in an opera house, accompanied by an orchestra or smaller musical ensemble, which since the early 19th century has been led by a conductor. Although musical theatre is closely related to opera, the two are considered to be distinct from one another.