Khovanshchina (Russian: Хованщина, IPA: [xɐˈvanʲɕːɪnə] (listen), sometimes rendered The Khovansky Affair) is an opera (subtitled a 'national music drama') in five acts by Modest Mussorgsky. The work was written between 1872 and 1880 in St. Petersburg, Russia. The composer wrote the libretto based on historical sources. The opera was almost finished in piano score when the composer died in 1881, but the orchestration was almost entirely lacking.

Like Mussorgsky's earlier Boris Godunov, Khovanshchina deals with an episode in Russian history, first brought to the composer's attention by his friend the critic Vladimir Stasov. It concerns the rebellion of Prince Ivan Khovansky, the Old Believers, and the Muscovite Streltsy against the regent Sofia Alekseyevna and the two young Tsars Peter the Great and Ivan V, who were attempting to institute Westernizing reforms in Russia. Khovansky had helped to foment the Moscow Uprising of 1682, which resulted in Sofia becoming regent on behalf of her younger brother Ivan and half-brother Peter, who were crowned joint Tsars. In the fall of 1682 Prince Ivan Khovansky turned against Sofia. Supported by the Old Believers and the Streltsy, Khovansky – who supposedly wanted to install himself as the new regent – demanded the reversal of Patriarch Nikon's reforms. Sofia and her court were forced to flee Moscow. Eventually, Sofia managed to suppress the so-called Khovanshchina (Khovansky affair) with the help of the diplomat Fyodor Shaklovity, who succeeded Khovansky as leader of the Muscovite Streltsy. With the rebellion crushed, the Old Believers committed mass suicide (in the opera, at least).

Nikolai Rimsky-Korsakov completed, revised, and orchestrated Khovanshchina in 1881–1882. In 1958 Dmitri Shostakovich was commissioned to revise and reorchestrate the opera for a film version released the following year. It is the Shostakovich version which is now usually performed. In 1913 Igor Stravinsky and Maurice Ravel made their own arrangement at Sergei Diaghilev's request. When Feodor Chaliapin refused to sing the part of Dosifey in any other orchestration than Rimsky-Korsakov's, Diaghilev's company employed a mixture of orchestrations which did not prove successful. The Stravinsky-Ravel orchestration was forgotten, except for Stravinsky's finale, which is still sometimes used.

Although the background of the opera comprises the Moscow Uprising of 1682 and the Khovansky affair a few months later, its main themes are the struggle between progressive and reactionary political factions during the minority of Tsar Peter the Great and the passing of old Muscovy before Peter's westernizing reforms. It received its first performance in the Rimsky-Korsakov edition in 1886.