L'étoile is an opéra bouffe in three acts by Emmanuel Chabrier with a libretto by Eugène Leterrier and Albert Vanloo.

Chabrier met his librettists at the home of a mutual friend, the painter Gaston Hirsh, in 1875. Chabrier played to them early versions of the romance "O petite étoile" and the ensemble "Le pal, est de tous les supplices..." (with words by Verlaine which Leterrier and Vanloo found too bold and toned down). They agreed to collaborate and Chabrier set about composition with enthusiasm. The story echoes some of the characters and situations of Chabrier's Fisch-Ton-Kan.

L'étoile premiered on 28 November 1877 at Offenbach's Théâtre des Bouffes Parisiens. In its initial run the modest orchestra was appalled at the difficulty of Chabrier’s score, which was much more sophisticated than anything Offenbach wrote for the small boulevard theatre.

It was first performed outside France in Berlin on 4 October 1878, then in Budapest on 23 November 1878. In New York City in 1890, an English translation was titled The Merry Monarch, with new music by Woolson Morse. Chabrier's music fared no better in London in 1899, where the score was rewritten by Ivan Caryll for an adaptation at the Savoy Theatre called The Lucky Star. In Brussels in 1909, Chabrier's music was restored, and there was a performance at the Arts Décoratifs Exposition in Paris in 1925, conducted by Albert Wolff.

The operetta's first major revival was on 10 April 1941 at the Opéra-Comique in Paris under Nazi occupation, with Fanély Revoil, René Hérent, Lillie Grandval and André Balbon, at which time highlights were recorded, conducted by Roger Désormière; this production was revived in December 1946 with Revoil and Payen. New productions were mounted at the Opéra-Comique in October 1984 with Colette Alliot-Lugaz and Michel Sénéchal in leading roles, and in December 2007 with Jean-Luc Viala and Stéphanie d’Oustrac.

The first complete recording, by EMI in 1985, conducted by John Eliot Gardiner, followed a production at the Opéra National de Lyon the previous year starring Alliot-Lugaz, which was also filmed for television by FR3 in November 1985 and broadcast in 1986.

L'étoile has been performed with increasing frequency and further afield over recent years, with productions at Opera North in 1991, Glimmerglass and Maastricht in 2001, New York City Opera in 2003 (revived in March 2010), Toronto in 2005, Montreal and Cincinnati in 2006, Zurich in 2007 and Geneva in 2009. In 2010 it was performed at the Austin Lyric Opera, Texas, the Berlin State Opera (conducted by Simon Rattle) and Theater Bielefeld. A production by David Alden has been mounted in repertory at Frankfurt Opera in 2010 and 2011. New Sussex Opera staged a touring production in Sussex and London in English, as Lucky Star, in 2013 (conducted by Nicholas Jenkins).