Henri Pousseur (born 23 June 1929, Malmedy, died 6 March 2009) was a Belgian composer. Pousseur studied at the Academies of Music in Liège and in Brussels from 1947 to 1953. He was closely associated with Pierre Froidebise and André Souris. He encountered Pierre Boulez, Karlheinz Stockhausen and Luciano Berio and thereafter devoted himself to avant-garde research. Beginning around 1960, he collaborated with Michel Butor on a number of projects, most notably the opera Votre Faust (1961–68).