Alexander Sergeyevich Dargomyzhsky (February 14, 1813–January 17, 1869) is a great Russian composer of 19th century. He filled the gap in Russian opera composition between Mikhail Glinka and the later generation of The Five and Tchaikovsky.

Dargomyzhsky studied in St. Petersburg. He met Glinka in 1833 when he was already known as a talented composer. He composed his famous opera Esmeralda (based on Victor Hugo's The Hunchback of Notre Dame) in 1839 (performed 1847). Another his opera Rusalka was performed in 1856. But he hadn’t the real success either abroad or at home, except in Belgium. But situation changed in the 1860s, when he became the elder statesman (still not a member though) of The Five.

His opera The Stone Guest was the last. It is his most famous work, known as a pioneering effort in melodic recitative. But the composer died and left it unfinished. Later it was finished by Rimsky-Korsakov and César Cui and Nikolai. And it was by The Five for what was perceived as its progressive approach to operatic expression. It was premiered in 1872, but never became a lasting standard operatic repertoire item.

Dargomyzhsky left other unfinished opera projects as well. For example he didn’t finish Pushkin's Poltava. His other compositions also include piano pieces, numerous songs, and some orchestral works.