Alexander Sergeyevich Taneyev (Russian: Алекса́ндр Серге́евич Тане́ев, also transliterated as Taneiev, Tanaiev, Taneieff, and Taneyeff in English; January 17, 1850 – February 7, 1918) was a Russian composer of the late Romantic era, specifically of the nationalist school. Among his best works were three string quartets, believed to have been composed between 1898 - 1900.

Alexander Taneyev is not well known outside Russia. His name is often confused with that of his distant cousin Sergei Taneyev (1856 - 1915) (who was sometimes known as the "Russian Brahms" due to the emphasis he placed on structural thinking over orchestration and texture).

Taneyev was the father of Anna Vyrubova, a lady in waiting and best friend of Tsarina Alexandra. Vyrubova was best known for her relationship with the Romanov family and for her attachment to the starets Grigori Rasputin.

Alexander Taneyev inherited an enthusiasm for music from his parents. He was dissuaded from pursuing a career as a musician due to his position in the Russian upper class. After studying at university, he entered the Russian civil service, succeeding his father as Director of the Imperial Chancellery. After 1900 he was the head of the folksong collection project of the Russian Geographical Society. Several of the songs collected during this period were later arranged and published by Anatoly Lyadov.

Taneyev pursued musical studies in Germany and later in Petersburg, where he became a student of Nikolai Rimsky - Korsakov. Taneyev's situation at this time bore similarities to that of fellow composer Alexander Borodin. Both were composers whose main occupation was not in music (Borodin was a chemistry professor; Taneyev held a bureaucratic post). It was rumored that Taneyev kept a score that he was working on hidden beneath official documents so that he might pen a few notes between appointments.

Taneyev's compositional output was large: two operas, three symphonies, several pieces for orchestra, numerous choral works, and a considerable amount of chamber music including three string quartets. The influence on his work of the other Russian nationalist composers, such as Rimsky - Korsakov, Balakirev and Lyadov, is often noted.

Taneyev married Nadezhda Illarionovna Tolstoy (1860 - 1937). They had three children: Anna Vyrubova (1884 - 1964); Sergei Alexandrovich (1886 - 1975); and Alexandra Alexandrovna (1888 - 1968), who married Alexander Erikovich von Pistohlkors, the stepson of Grand Duke Paul Alexandrovich of Russia.