Marion Bauer (1882-1955) was an American composer, critic, teacher and author who played an important role in the development of modern music in the United States. Born in Washington state, she studied in the United States and Europe, including work in Paris that placed her close to emerging modernist currents.

Bauer wrote orchestral music, chamber works, piano pieces, songs and choral music. She was also a widely read writer on music, and her book Twentieth Century Music helped introduce modern composition to American students and listeners.

Her own music moves between late Romantic expressiveness, impressionist colour and more advanced harmonic languages. She was less interested in dogma than in expanding the expressive possibilities available to American composers.

As a teacher at New York University and Juilliard, and as a founder of musical organisations, Bauer helped shape the infrastructure of American modern music. Her work is part of a generation whose advocacy and composition both widened the field.