Juliette is an opera by Bohuslav Martinů, who also wrote the libretto, in French, based on the play Juliette, ou La clé des songes by the French author Georges Neveux. A libretto in Czech was later prepared for its premiere which took place at the Prague National Theatre on 16 March 1938. Juliette has become widely considered as Martinů's masterpiece.

The Bielefeld Opera is the venue of Städtische Bühnen Bielefeld in Bielefeld, Germany. It is a Dreisparten Haus, offering plays, music, and ballet. The main performance venue is the Stadttheater am Niederwall, built in 1904 and extensively renovated from 2004 to 2006. It is the largest theater in East Westphalia, offering 500 performances annually. It is under the direction of Michael Heicks; its resident orchestra is the 72-member Bielefeld Philharmonic Orchestra that also performs symphonic concerts at the Rudolf-Oetker-Halle.