Bluebeard's Castle is a one-act expressionist opera by Hungarian composer Béla Bartók. The libretto was written by Béla Balázs, a poet and friend of the composer, and is written in Hungarian, based on the French literary tale La Barbe bleue by Charles Perrault. The opera lasts only a little over an hour and there are only two singing characters onstage: Bluebeard (Kékszakállú), and his new wife Judith (Judit); the two have just eloped and Judith is coming home to Bluebeard's castle for the first time.

Bluebeard's Castle, Sz. 48, was composed in 1911 (with modifications made in 1912 and a new ending added in 1917) and first performed on 24 May 1918 at the Royal Hungarian Opera House in Budapest. Universal Edition published the vocal (1921) and full score (1925). The Boosey & Hawkes full score includes only the German and English singing translations while the Dover edition reproduces the Universal Edition Hungarian/German vocal score (with page numbers beginning at 1 instead of 5). A revision of the UE vocal score in 1963 added a new German translation by Wilhelm Ziegler, but seems not to have corrected any errata. Universal Edition and Bartók Records has published a new edition of the work in 2005 with a new English translation by Péter Bartók, accompanied by an extensive errata list