Alexand(e)r Dmitriyevich Kastalsky (Russian: Александр Дмитриевич Кастальский) (28 November [O.S. 16 November] 1856 – 17 December 1926) was a Russian composer and folklorist. Kastalsky was born in Moscow to protoiereus Dmitri Ivanovich Kastalsky (1820–1891). He studied music theory, composition and the piano at the Moscow Conservatory. In 1887 he started teaching piano at Moscow Synodal School, and in 1891 became assistant precentor of the Moscow Synodal Choir. He was director of both from 1910–1918 until the school was dissolved and merged with the choral faculty of the Conservatory, and the choir was forced to move from sacred to folk repertory.