Adriana Lecouvreur is an opera in four acts by Francesco Cilea to an Italian libretto by Arturo Colautti, based on the 1849 play Adrienne Lecouvreur by Eugène Scribe and Ernest Legouvé. It was first performed on 6 November 1902 in Milan.

The same play by Scribe and Legouvé which served as a basis for Cilea's librettists was also used by at least three different librettists for operas carrying exactly the same name, Adriana Lecouvreur, and created by three different composers. The first was an opera in three acts by Tommaso Benvenuti (premiered in Milan in 1857). The next two were lyric dramas in 4 acts by Edoardo Vera (to a libretto by Achille de Lauzières) which premiered in Lisbon in 1858, and by Ettore Perosio (to an anonymous libretto), premiered in Geneva in 1889. After Cilea created his own Adriana, however, none of those by others were performed anymore and they remain largely unknown today.

The opera is based on the life of the French actress Adrienne Lecouvreur (1692–1730). While there are some actual historical figures in the opera, the episode it recounts is largely fictional, its death-by-poisoned violets plot device often signalled as verismo opera's least realistic. It is often condemned as being among the most confusing texts ever written for the stage, and cuts that have often been made in performance only make the story harder to follow. The running time of a typical modern performance is about 135 minutes (excluding intervals).

The opera premiered at the Teatro Lirico, Milan, on 6 November 1902, with the well-known verismo soprano Angelica Pandolfini in the title role, Enrico Caruso in the role of Maurizio, and the lyric baritone Giuseppe De Luca as Michonnet.

The opera was first performed in the United States by the San Carlo Opera Company on January 5, 1907 at the French Opera House in New Orleans with Tarquinia Tarquini in the title role. It gained its Metropolitan Opera premiere on 18 November 1907 (in a performance starring Lina Cavalieri and Caruso). It had a run of only three performances that season, however, due in large part to Caruso's ill-health. Subsequently, it was revived at the Met from time until a new production was commissioned in 1963. That 1963 production continued to be remounted at the same theatre, with differing casts, for the next few decades. It was in the lead role of this opera that the Spanish tenor Plácido Domingo made his Met debut in 1968, alongside Renata Tebaldi in the title role. He sang again in Adriana Lecouvreur in February 2009, although his voice was by then in decline.

The title role in Adriana Lecouvreur has always been a favorite of sopranos with large voices, which tend to sit less at the very top of their range. This part has a relatively low tessitura but requires great vocal power, and is a meaty and challenging one to tackle on a dramatic level – especially during the work's so-called "Recitation" and death scene. Famous Adrianas of the past 75 years have included Claudia Muzio, Magda Olivero, Leyla Gencer, Montserrat Caballé, Renata Tebaldi, Raina Kabaivanska, Renata Scotto, Mirella Freni and Joan Sutherland. Angela Gheorghiu tackled the role at the Royal Opera, London in 2010 with Jonas Kaufmann as Maurizio.."

A recording of part of the opera's last act duet "No, più nobile", rejigged into a self-contained tenor aria, was made by Caruso as early as 1902 for the Gramophone & Typewriter Company in Milan and its affiliates, with Cilea at the piano.

In Decca's 1990 complete performance of the work, with Dame Joan Sutherland as the female lead, the Australian conductor Richard Bonynge made sure that he restored a long-lost passage that Cilea had cut originally from the score. Its restoration made the opera's plot more transparent.