Leonard Treash (January 1, 1909 in Pennsylvania – January 31, 1996 in Rochester, New York) was an American bass, opera director, and educator. As a performer he sang leading opera roles throughout the United States under such conductors as Fritz Reiner, Leopold Stokowski, Artur Rodzinski, and Erich Leinsdorf. He was particularly active as a performer with opera companies in Philadelphia, and is especially remembered as the long time director of the opera program at the Eastman School of Music, a post he held for nearly 30 years. He also served as General Director of Chautauqua Opera for 10 seasons and was the first President of the National Opera Association from 1955-1956.