Denis William Stevens CBE (2 March 1922 – 1 April 2004) was a British musicologist specialising in early music, conductor, professor of music and radio producer.
He was born in High Wycombe, Buckinghamshire and attended the Royal Grammar School there. From that school, he won a scholarship to read modern languages at Jesus College, Oxford in 1940. During World War II, he served as a cryptanalyst in India and Burma. After the war, he returned to Oxford to complete his degree. From 1949 to 1954, he was a producer at the BBC Third Programme.
Stevens completed the task of producing the Supplementary Volume to the 5th edition of Grove's Dictionary of Music and Musicians, which Eric Blom had not been able to complete by the time of his death in 1959. The Supplementary Volume was published in 1961. He also contributed to The Stereo Record Guide through 1968.
From 1964 to 1976, he was professor of musicology at Columbia University, New York. In 1995, he was appointed as visiting professor at Goldsmiths College, London, the institution which now houses his extensive Monteverdi library.
Best known for his work on early baroque Italian composers, especially Claudio Monteverdi, and for his pioneering concerts and recordings with the Accademia Monteverdiana (which he founded), Stevens was appointed a Commander of the Order of the British Empire (CBE) in 1984.