Marcelo Koc (4 June 1918 in Vitebsk, Belarus – 26 October 2006 in Buenos Aires) was an Argentinian composer.
Koc studied at the Academy of Music in Lódz, Poland and in 1938 went to Buenos Aires where he continued his education with Jacobo Ficher, Guillermo Graetzer and Juan Carlos Paz.
His Å“uvre consists of more than 101 works and includes orchestral and concertante works, chamber music, piano and vocal music.