One of the most viable trends in the compositional practice of the twentieth and twenty-first centuries is the blurring and breaking of boundaries between classical and popular styles. Toward the end of the nineteenth century this blurring of boundaries resulted in the genre of cabaret. My document demonstrates that classical composers of various nationalities and compositional styles experimented in this new genre of cabaret. It traces the history of the cabaret movement from its origins through World War II and provides a detailed history of the cabaret songs of four classical composers: Erik Satie’s cabaret songs for Vincent Hyspa, Arnold Schoenberg’s Brettl-Lieder, Kurt Weill’s cabaret songs from his Paris years, and Benjamin Britten’s Cabaret Songs. Through musical analysis this document shows that their cabaret songs reflect the influence of popular idioms as well as each composer’s own classical style.