Leo Blech was a German opera composer and conductor who is perhaps most famous for his work at the Königliches Opernhaus from 1906 to 1937, and later as the conductor of Berlin's Städtische Oper from 1949 to 1953. Blech was known for his reliable, clear, and elegant performances, especially of works by Wagner, Verdi, and Bizet's Carmen, and for his sensitivity as an accompanist.