Sir Orfeo is an anonymous Middle English Breton lai dating from the late 13th or early 14th century. It retells the story of Orpheus as a king who rescues his wife from the fairy king. The folk song Orfeo is based on this poem.

A Breton lai, also known as a narrative lay or simply a lay, is a form of medieval French and English romance literature. Lais are short, rhymed tales of love and chivalry, often involving supernatural and fairy-world Celtic motifs. The word "lay" or "lai" is thought to be derived from the Old High German and/or Old Middle German leich, which means play, melody, or song, or as suggested by Jack Zipes in The Oxford Companion to Fairy Tales, the Irish word laid (song).