O'Brien, Richard O'Brien, Tim O'Callanain, Niall O'Carolan, Turlough O'Connell, Ryan O'Connor, Ella Yelich O'Farrill, Chico O'Gorman, Peter O'Hara, Geoffrey O'Hara, Michael O'Laoire, Lillis O'Leary, Jessica (editor) O'Mahoney, Terry O'Neal, Barry O'Neill, Francis O'Neill, Jackie O'Neill, Paul O'Neill, Susan O'Regan, Tarik O'Reilly, John O'Reilly, Kim Oakland, Ben Oare, Michael OASIS Oberfeld, Casimir Oberst, Fritz Obijalska, Dorota Obradors, Fernando Obrecht, Jacob Obrovska, Jana Obst, Michael Ocampo, Mauricio Cardozo Ochs, Siegfried Ockeghem, Johannes Ockelford, Adam Oddone, Edoardo Odeh-Tamimi, Samir Odeh-Tamini, Samir Odell, Tom Oden, Annette Odo, Franklin Odone, Alberto Oerding, Johannes Oermann, Nils Ole Offenbach, Jacques Ogiński, Michał Kleofas Öhman, Karin Ohse, Reinhard Oja, Carol J. Okamoto, Shinsuke Okazaki, Miles Okoshi, Tiger Olah, Tiberiu Olatunji, Babatunde Olazabal, Tirso Oldenkamp, Michiel Oldroyd, George Oliva, John Olivadoti, Joseph Oliver, Joseph King Oliver, Julian Oliver, Nancy Oliver, Sy Olivero, Betty Olivieri Sangiacomo, Elisa Olson, Lynn Freeman Olson, Robert Olson, Tawnie Olsson, Milton Olusola, Kevin Omar, Don Omartian, Michael Ondrasik, John Ondrícek, František Ondruš, Ján One Republic Ongarello, Antonio ónis Ono, Yoko Onovwerosuoke, Fred Ónozó János Onyeji, Christian Oosterhout, Arjen Oppo, Franco Oprea, Alin Cristian Oram, James Orbán György Orban, Marcel Orbison, Roy Orefice, Giacomo Orefici, Alberto Orff, Carl Orkisz, Andrzej Orloff-Tschekorsky, Tatjana Orologio, Alessandro Oromszegi Ottó Orr, J. Orsi, Romeo Országh Tivadar Ort, Jirí Ortelli, Antonio Ortiz, Diego Ortiz, Suzzette Ortiz-Alvarado, Graciela Paraskevaídis William Ortolani, Riz Orton, Beth Osborn, Brad Osborne Osborne, Anthony Osborne, Richard Osborne, Tony Osbourn, Leslie Osbourne, Ozzy Osentowski, Francis Osgood, Charles Oshrat, Kobi Osorio, Nuno Ospald, Klaus Osse, Klaus Ostendorf, Jens-Peter Osterling, Eric Ostransky, Leroy Ostrzyga, Michael Oswald, Albert Oswald, Gerald Otros, Y. Ott Rezső Ott, Daniel Ott, Eugen Ott, Karin Otten, Mark Otterstedt, Annette Ovadia, Moni Ovcharenko, Halyna Overduin, Jan Ovokaitys, Cindy Owen, Barbara Owen, Randy Owen, Teodora Owen, William Owenby, Chris Owens, James T. Owens, Jessie Ann Owens, Jimmy Owens, Matthew Owens, Thomas Owsinsky, Bobby Oxa, Anna Ozi, Etienne Ozim, Igor (Hrsg.) O'Loughlin, Sean (instrumentation by) O'Loughlin, Sean (arranged by) O'Neill, Jackie (arranged by) O'Regan, Noel (edited by) Oberbek, Jan (edited by) Obst, Michael (edited by) Obst, Michael (arranged by) Obst, Michael (KA) (arranged by) Ocean, Johny (instrumentation by) Ocker, Marshall (instrumentation by) Oddo, John (instrumentation by) Odermatt, Arnold (edited by) Oechsle, Siegfried (edited by) Oeser, Fritz (translated by) Oeser, Fritz (edited by) Oeser, Fritz (words by) Oeser, Fritz (transcribed by) Oesterle, Louis (edited by) Ofburg (instrumentation by) Ogonovsky, Margaret (arranged by) Ohanian, David (arranged by) Ohmen, Wilhelm (edited by) Ohmiya, Makoto (edited by) Oistrach, Igor (piano score by) Oldenkamp, Michiel (edited by) Oldman, Cecil B. (edited by) Oleskiewicz, Mary (edited by) Oliva, Petr (edited by) Olson, Lynn Freeman (edited by) Olson, Lynn Freeman (arranged by) Ondra, Jaroslav (arranged by) Ondrícek, František (transcribed by) Ongarello, Antonio (arranged by) Ongarello, Antonio (transcribed by) Ónozó János (edited by) Opp, Walter (edited by) Oppermann, Annette (edited by) Orbán György (transcribed by) Orbán György (edited by) Orbán György (piano score by) Orbán György (composer-contributor) Orbán György (edited by) Orbán György (arranged by) Orbán Ottó (translated by) Orbaugh, William (arranged by) Orel, Alfred (edited by) Orel, Alfred (words by) Orenstein, Arbie (edited by) Orford, John (editor) (edited by) Orgelbuchkommission Baden, Elsaß, Lothringen und Pfalz (edited by) Ormay Imre (translated by) Ormay Imre (words by) Oromszegi Ottó (edited by) Orphee, Matanya (edited by) Országh Tivadar (transcribed by) Országh Tivadar (transcribed for violin and piano) Országh Tivadar (compiled by) Ortega, J. (transcribed and edited by) Ortega, J. (edited by) Ortiz, Juan (instrumentation by) Osborne, Tony (edited by) Ostendorf, Jens-Peter (edited by) Osterling, Eric (transcribed by) Osterling, Eric (instrumentation by) Osthoff, Helmuth (edited by) Osthoff, Wolfgang (edited by) Osvát Erzsébet (words by) Oswald, Gerald (instrumentation by) Ötsch, Barbara (edited by) Ott Rezső (piano score by) Otterstedt, Annette (edited by) Oud, Thijs (arranged by) Oud, Thijs (instrumentation by) Over, Bertold (edited by) Owen, Don (instrumentation by) Owen, Teodora (author) Ozawa, Kazuko (edited by) Ozim, Igor (edited by) Ozsvárt Viktória (edited by)