Modest Petrovich Mussorgsky (March 21, 1839 - March 28, 1881; sometimes spelt Modeste Moussorgsky), was a Russian composer.

He was a member of The Five, the group of composers under the leadership of Mily Balakirev dedicated to producing a distinctly Russian kind of music. Mussourgsky is best remembered today for his orchestral work St. John's Night on the Bare Mountain (commonly known as Night on Bald Mountain), and his cycle of piano pieces, Pictures at an Exhibition, written in commemoration of his friend, the architect Viktor Hartmann. (Years after Mussorgsky's death, a well known orchestral arrangement of the piece was made by Maurice Ravel.) Mussorgsky's opera, Boris Godunov is also well known.

Among his other works are a number of songs, including three song cycles: The Nursery (1872), Sunless (1874) and Songs & Dances of Death (1877).

Modest Petrovich Mussorgsky died on March 28, 1881 and was interred in Tikhvin Cemetery at the Alexander Nevsky Monastery, in St. Petersburg, Russia.