Lady Macbeth of the Mtsensk District is an opera in four acts by Dmitri Shostakovich, his Op.29. The libretto was written by Alexander Preis and the composer, and is based on the novel Lady Macbeth of Mtsensk District by Nikolai Leskov. The opera is sometimes referred to informally as Lady Macbeth when there is no confusion with Verdi's Macbeth. It was first performed on 24 January 1934 at the Leningrad Maly Operny. Shostakovich dedicated the opera to his first wife, the physicist Nina Varzar.

The work incorporates elements of expressionism and verismo. It tells the story of a lonely woman in 19th century Russia, who falls in love with one of her husband's workers and is driven to murder.

Despite great early success, on both popular and official levels, Lady Macbeth was the vehicle for a general denunciation of Shostakovich's music by the Communist Party in early 1936. After being condemned by an anonymous article (sometimes attributed to Joseph Stalin) in Pravda, the Communist Party newspaper, it was banned in the Soviet Union for almost thirty years. Many people thus know the opera primarily for its role in the history of censorship.

The composer later revised the opera, now renamed Katerina Izmailova, his Op. 114. It features two new entr’actes, a major revision to Act 1 Scene 3, and some smaller changes elsewhere. The revised version was first performed on 26 December 1962 in Moscow at the Stanislavsky-Nemirovich-Danchenko Musical Theatre. Since Shostakovich's death the original version is more often performed.