John Harger Stewart (born March 31, 1940 in Cleveland) is an American tenor, conductor, and voice teacher who had an active international singing career in concerts and operas from 1964 to 1990. He began his career singing regularly with the Santa Fe Opera from the mid-1960s through the early 1970s; after which he appeared only periodically in Santa Fe up through the mid-1980s. He was particularly active with the New York City Opera during the 1970s and 1980s, and with the Frankfurt Opera from the mid-1970s through 1990. He also appeared as a guest artist with several other important American opera companies, including the Metropolitan Opera and the Washington National Opera, and at other European opera houses like the De Nederlandse Opera in Amsterdam, the Deutsche Oper Berlin, the Grand