This article argues that Brecht’s unique musicality as a poet led to a rich and rarely paralleled collaboration with musical composers. While the young Brecht sketched out his own music for his early poetry and songs, he soon turned to professional composers as partners. The article focuses on Brecht’s three major musical collaborators, Kurt Weill, Hanns Eisler, and Paul Dessau. In addition to the innovative works that Brecht created with these composers, they also stimulated important theoretical writings that led to new forms of opera, as in Brecht/Weill’s Mahagonny and The Threepenny Opera, or a revolutionary aesthetics of film music, as in Eisler/Adorno’s Composing for the Films, which is strongly influenced by Brecht.