O'Boyle, Sean: Australian composer.
O'Connell, Kevin: (1958- ), Derry, Ireland. Picture, biography, and selected works, from the Contemporary Music Centre, Ireland.
O'Connor, Tom: Picture, biography, and works.
O'Farrell, Anne Marie: (1966- ), Dublin, Ireland. Picture, biography, and selected works, from the Contemporary Music Centre, Ireland.
O'Leary, Jane: (1946- ), Hartford, Connecticut. Picture, biography, and selected works, from the Contemporary Music Centre, Ireland.
O'Leary, Martin: (1963- ), Dublin, Ireland. Picture, biography, and selected works, from the Contemporary Music Centre, Ireland.
O'Neill, Nicholas: (1970- ), Cheltenham, England. Picture, biography, selected works, and sound file, from the British Composers World Wide Web Project.
O'Quinn, David: Compositions with scores and sound using Sibelius Music, and links.
Obrovska, Jana: (1930- ), Prague, Czech Republic. Biography and selected works, from the Czech Music Information Project.
Ocana, Anthony: (1980- ), Santiago, Dominican Republic. Pictures, biography, news, and sound files.
Ocker, David: (1951- ) Picture, biography, about the music, list of works, and about 'Pynchon,' from Leissure Music Planet.
Odstrcil, Karel: (1930- ), Valaske Mezirici, Czech Republic. Biography and selected works from the Czech Music Information Project.
Oehring, Helmut: (1961- ), Berlin, Germany. Biography from Boosey & Hawkes.
Oesterle, Michael: (1968- ), Ulm, Germany. Picture, biography, and works.
Ogdon, Will: Picture, biography, and works, from the American Music Center.
Ogle, Brian: Picture, biography, and list of works.
Oja, Esko: (1973- ), Tallinn, Estonia. Picture, biography, and works, from edition49.
Olive, Vivienne: (1950- ), London, England. Picture, biography, and list of works and recordings, from the Australian Music Centre.
Oliver, Harold: (1942- ) Includes biographical sketch, a catalog of his compositions, scores and sound files, and a brief essay.
Oliver, John: (1959- ), Vancouver, British Columbia. Picture, biography, selected works, and CDs, from the Canadian Music Centre.
Olivero, Betty: (1954- ), Tel Aviv, Israel. Picture, biography, selected works, and CDs.
Olofsson, Kent: (1962- ), Karlskrona, Sweden. Biography from the Swedish Music Information Center.
Olsen, Tim: (1961- ), St. Paul, Minnesota. Biography, works, and events, from Vischer Ferry Music Publishing Co.
Oosterbaan, André: (1947- ), Amsterdam, Holland. Biography and list of works and recordings, from the Australian Music Centre.
Oppedisano, Marco: (1971- ) Picture, biography, selected works with sound files and information, from Vox Novus.
Orenstein, Joyce E.: List of works from New York Women Composers.
Orgad, Ben-Zion: (1926- ), Gelsenkirchen, Germany. Picture and biography, from the Israel Music Institute.
Orgee, Andy: (1958- ) Picture, biography, compositions, performances, and audio files.
Orlovich, Matthew: (1970- ), Sydney, Australia. Picture, biography, compositions, recordings, performances, and press.
Ornstein, Leo: (1892-2002) Picture and biography, from Other Minds.
Orr, Robin: (1909- ), Brechin, England. Picture, biography, list of works, and performances.
Ortiz Alvarado, William: Picture, biography, list of works, recordings, and reviews.
Orton, Richard: (1940- ), Derby, England. Picture, biography, works, commissions, recordings, and news, from Unique Music.
Osborne, Nigel: (1948- ) Picture and biography.
Ostertag, Bob: (1957- ), Albuquerque, New Mexico. Biography, CDs, photographs, and reviews.
Ottzen, Susan: Composer, classical and jazz harpist, and teacher. Picture, biography, and sound files.
Ouellette, Antoine: (1960- ), Montréal, Québec. Picture, biography, list of works, and CDs, from the Canadian Music Centre.
Owens, Terry Winter: Picture, biography, commissions and awards, performances, and list of works, from the American Music Center.