Ó Cearbhalláin, Toirdhealbhach O'Brien, Conor J. O'Brien, Richard O'Brien, Tim O'Callanain, Niall O'Carolan, Turlough O'Connell, Finneas O'Connell, Ryan O'Connor, Ella Yelich O'Duffy, Grace O'Farrill, Chico O'Gorman, Peter O'Hara, Geoffrey O'Hara, Michael O'Keefe, Laurence O'Laoire, Lillis O'Leary, Jessica (editor) O'Mahoney, Terry O'Mara, Peter O'Neal, Barry O'Neill, Francis O'Neill, Jackie O'Neill, John O'Neill, Paul O'Neill, Susan O'Regan, Tarik O'Reilly, John O'Reilly, Kim O'Reilly, Roisin Ann O. Gutman Oakland, Ben Oare, Michael OASIS Oberfeld, Casimir Oberst, Fritz Oberthur, Carl Obijalska, Dorota Obolskaja N. Obradors, Fernando Obrecht, Jacob Obrovska, Jana Ocampo, Mauricio Cardozo Ochs, Siegfried Ockeghem, Johannes Ockelford, Adam Oddo, John Oddone, Edoardo Odeh-Tamimi, Samir Odeh-Tamini, Samir Odell, Tom Oden, Annette Odgren, Jim Odo, Franklin Odone, Alberto Odstrcil, Karel Oehring, Helmut Oerding, Johannes Oermann, Nils Ole Oesten, Theodor Offenbach Jacques Offenbach, Jacques Offer, Charles Offermann, Thomas Ogarkova N. A. Oginski, Michal Kleofas Ogorodnov, V. Ogorodnova, Dina Izrailevna Ogorodnova-Dukhanina, Tamara Ohana, Maurice Ohse, Reinhard Oja, Carol J. Okamoto, Shinsuke Okazaki, Miles Okhalova I. - Averjanova O. Okhalova I. - Korzun K. Okoshi, Tiger Okudzhava Bulat Shalvovich Okunev German Olafsdottir, Hallfridur Olah, Tiberiu Olatunji, Babatunde Olazabal, Tirso Oldenkamp, Michiel Oldham, Arthur Oldroyd, George Olechowski, Józef Oler, Kim Olias, Lotar Oliva, John Olivadoti, Joseph Oliveira Pinto, Tiago de Oliver, Joseph King Oliver, Julian Oliver, Nancy Oliver, Sy Olivero, Betty Olivier, François Olivier, Philippe Olivieri Sangiacomo, Elisa Oliviero, N. Olson, Lynn Freeman Olson, Robert Olson, Tawnie Olsson, Milton Olsvay Endre Oltmann, Uwe Olusola, Kevin Omar, Don Omartian, Michael Omelchuk, Oxana Ondrasik, John Ondrícek, František Ondruš, Ján One Direction One Republic Ongarello, Antonio Ono, Yoko Onovwerosuoke, Fred Ónozó János Onyeji, Christian Oosterhout, Arjen Oppo, Franco Opurina Tamara Oquin, Wayne Oram, James Oratovskij A. (ed.) Orbán György Orban, Marcel Orbison, Roy Ordasi Péter Ordońez, Carlos d' Orefice, Giacomo Orefici, Alberto Oreus V. Orff, Carl Orff, Gertrud Oriol, Emmanuel Orkisz, Andrzej Orlandi, Paolo Orloff-Tschekorsky, Tatjana Orlov, G. Orlova, Darja Sergeevna Orlowsky, David Orochko Aleksej Orologio, Alessandro Oromszegi Ottó Orr, J. Orr, Robin Orrego-Salas, Juan Orsi, Romeo Országh Tivadar Ort, Jirí Ortelli, Antonio Ortiz, Diego Ortiz, Suzzette Ortiz-Alvarado, Graciela Paraskevaídis William Ortmeier, Philipp Ortolani, Riz Orton, Beth Osborn, Brad Osborne Osborne, Anthony Osborne, Nigel Osborne, Reginald Osborne, Richard Osborne, Tony Osbourn, Leslie Osbourne, Ozzy Oscar Peterson Osentowski, Francis Osgood, Charles Oshrat, Kobi Osin I. (ed.) Oskolkov Sergej Aleksandrovich Osmond, Marcella Osorio, Nuno Osovitskaja Z. Ospald, Klaus Osse, Klaus Ostendorf, Jens-Peter Osterling, Eric Ostleitner, Elena Ostransky, Leroy Ostrovskaja Yanina - Frolova Lyudmila Ostrzyga, Michael Oswald, Albert Oswald, Gerald Oswald, Julian Othmayr, Caspar Otros, Y. Ott Rezső Ott, Eugen Ott, Karin Otte, Hans Otten, Mark Otterstedt, Annette Otto, Uwe Ouzounoff, Alexandre Ovadia, Moni Ovcharenko, Halyna Ovchinnikov Vyacheslav Overduin, Jan Overthrow, David Ovokaitys, Cindy Owen Edwards, John Owen, Barbara Owen, Randy Owen, Teodora Owen, William Owenby, Chris Owens, James T. Owens, Jessie Ann Owens, Jimmy Owens, Matthew Owens, Terry Winter Owens, Thomas Oxa, Anna Oxtoby, Charles Ozi, Étienne Ozi, Etienne Ó Cearbhalláin, Toirdhealbhach (author) O'Connell, Ryan (edited by) O'Connor-Morris, Geoffrey (arranged by) O'Leary, Mark (edited by) O'Loughlin, Sean (instrumentation by) O'Loughlin, Sean (arranged by) O'Loughlin, Sean (arranged by) O'Loughlin, Sean (edited by) O'Neill, Jackie (arranged by) O'Neill, John (author) O'Neill, Norman (edited by) O'Neill, Norman (arranged by) O'Regan, Noel (edited by) OASIS (author) Oberbek, Jan (edited by) Oberschmidt, Juergen (edited by) Obert, Salome (edited by) Obrecht, Jacob (author) Obst, Michael (edited by) Obst, Michael (arranged by) Ocean, Johny (instrumentation by) Ochs, Siegfried (author) Ocker, Marshall (instrumentation by) Oddo, John (instrumentation by) Odermatt, Arnold (edited by) Odom, Lawrence T. (arranged by) Oechsle, Siegfried (edited by) Oehl, Kurt (edited by) Oehler, Regina (author) Oehler, Thomas (arranged by) Oehrli, Fabian (arranged by) Oeser, Fritz (translated by) Oeser, Fritz (edited by) Oeser, Fritz (words by) Oeser, Fritz (transcribed by) Oesterle, Louis (edited by) Oetke, Herbert (edited by) Ofburg (instrumentation by) Ogaard, Sigurd (arranged by) Ogonovsky, Margaret (arranged by) Ohanian, David (arranged by) Ohmen, Wilhelm (arranged by) Ohmen, Wilhelm (edited by) Ohmen, Wilhelm (edited by) Ohmiya, Makoto (edited by) Okuljar, Tadeusz (edited by) Oldenkamp, Michiel (edited by) Oldman, Cecil B. (edited by) Oleskiewicz, Mary (edited by) Oliva, Petr (edited by) Oliver, David (edited by) Ollivo, Yann (piano score by) Olson, Kevin (edited by) Olson, Lynn Freeman (arranged by) Olson, Robert (edited by) Oltman, Matthew (edited by) Ondra Hirokawa, Joy (edited by) Ondra, Jaroslav (arranged by) Ondrícek, František (transcribed by) Ongarello, Antonio (edited by) Ongarello, Antonio (arranged by) Ónozó János (edited by) Opp, Walter (edited by) Oppermann, Annette (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) Orel, Alfred (edited by) Orel, Alfred (words by) Orelli, Matthias von (edited by) Orem, Philip (edited by) Orenstein, Arbie (edited by) Orff, Carl (author) Orff, Gertrud (edited by) Orford, John (edited by) Orga, Ates (edited by) Orledge, Robert (edited by) Orledge, Robert (arranged by) Ormandy, Eugene (arranged 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) Ortelt, Sabine (author) Ortiz, Juan (instrumentation by) Ortiz, Juan (edited by) Ortkemper, Hubert (edited by) Ortner, Franz (edited by) Osborne, Tony (edited by) Osborne, Tony (edited by) Oslansky, Stefan (author) Ostendorf, Jens-Peter (edited by) Osterling, Eric (edited by) Osterling, Eric (instrumentation by) Osthoff, Helmuth (edited by) Osthoff, Wolfgang (edited by) Osthoff, Wolfgang (edited by) Osvát Erzsébet (words by) Oswald, Gerald (instrumentation by) Oswald, Julian (author) Ötsch, Barbara (edited by) Ott Rezső (piano score by) Ott, Immanuel (edited by) Ott, Thomas (edited by) Ottensamer, Andreas (arranged by) Ottenschläger, Elke (author) Otterstedt, Annette (edited by) Oud, Thijs (instrumentation by) Oud, Thijs (arranged by) Outram, Martin (arranged by) Over, Bertold (edited by) Overton, David (edited by) Owen, Don (instrumentation by) Owen, Teodora (author) Ozawa, Kazuko (edited by) Ozawa, Kazuko (edited by) Ozim, Igor (edited by) Ozsvárt Viktória (edited by)