Carl Nielsen (1865–1931) was a Danish composer.

Carl Nielsen may also refer to: Carl O. Nielsen (1868–1950), Norwegian businessperson Carl Nielsen (rower) (1930–1991), Danish rower Carl Nielsen Academy of Music Carl Nielsen Edition, the composer's works in a bilingual practical-scientific version on a music philological basis Carl Nielsen International Music Competition, a competition for classical musicians held in Odense, Denmark Carl Nielsen Museum, a museum dedicated to the life of the composer

See also List of compositions by Carl Nielsen Carl Nilsson (disambiguation)