Composers – O
Composers: O'Boyle - Ogermann
- O'Boyle, Sean (b.1963)
- O'Brien, Charles (1882–1968)
- O'Brien, Christian
- O'Brien, Dennis
- O'Brien, Eugene (b.1945)
- O'Brien, Vincent (1871-1948)
- O'Callaghan, James (b. 1988)
- O'Canainn, Tomas
- O'Carolan, Turlough (1670–1738)
- O'Connell, Kevin (b.1958)
- O'Connor, Frederick (1870-1943)
- O'Connor, Mark (b.1961)
- O'Connor, Patrick (b.1942)
- O'Dell, Adam (b.1992)
- O'Donnell, James (b. 1961)
- O'Farrell, Anne-Marie (b.1966)
- O'Halloran, Dustin (b.1971)
- O'Hara, Chris
- O'Hara, Geoffrey (1882–1967)
- O'Hogan (né Lawrence Wright), Betsy
- O'Leary, Jane (b.1946)
- O'Meara, Rich (b.1957)
- O'Neill, Michael (b.1955)
- O'Neill, Nicholas (b.1970)
- O'Neill, Norman (1875–1934)
- O'Regan, Tarik (b.1978)
- O'Reilly, John (b.1940)
- O'Reilly, Meara
- O'Riordan, Kirk (b.1968)
- O'Rourke, Aidan (b. 1975)
- O'Rourke, Jim (b. 1969)
- O'Toole, Anthony
- Oakeley, Herbert (1830–1903)
- Oakes, Rodney (b.1937)
- Oakland, Ben (1907-79)
- Oakley, George (b. 1979)
- Oates, Janet (b.1970)
- Oberfeld, Casimir (1903-45)
- Oberleitner, Andreas (1786-?)
- Obermüller, Karola (b.1977)
- Oberthür, Charles (1819–95)
- Obiedov, Yuri (1904-79)
- Obiols, Mariano (1809-88)
- Obizzi, Domenico (fl.1620s)
- Oboussier, Robert (1900–57)
- Obradors, Fernando Jaumandreu (1897–1945)
- Obran, Marcel (1884-1958)
- Obrecht, Jacob (c.1457–1505)
- Obretenov, Svetoslav (1909-55)
- Obst, Michael (b.1955)
- Obuchov, Nikolaj (1892–1954)
- Obukhov, Nicolai (1892–1954)
- Occhipinti, David (b.1966)
- Ochando, Tomas
- Ochs, Siegfried (1858–1929)
- Ochs, Volker
- Ockeghem, Johannes (c.1420–1497)
- Ocón, Eduardo (1833–1901)
- Oda, Kazumasa (b. 1947)
- Odegaard, Martin (b. 1955)
- Odeh-Tamimi, Samir (b.1970)
- Odenhall, Staffan (b.1952)
- Odermatt, Gotthard (b.1974)
- Odin, Toke Brorson (b. 1982)
- Odoyevsky, Vladimir (1803–69)
- Odriozola, Ricardo (b. 1965)
- Oechsler, Elias (1850-1917)
- Oehler, Thomas
- Oehring, Helmut (b.1961)
- Oesten, Theodore (1813-70)
- Oesterle, Michael (b.1968)
- Oestreich, Carl (1800–40)
- Oevering, Reijnold Popma van (1692–1781)
- Ofenbauer, Christian (b.1961)
- Offenbach, Jacques (1819–80)
- Offner, Jan (1720-59)
- Ogden, Nigel (b.1954)
- Ogdon, John (1937–89)
- Ogdon, Will (1921-2013)
- Ogermann, Claus (1930–2016)
Composers: Oginski - Olrog
- Oginski, Michal Kleofas (1765–1833)
- Ogiński, Michał Kleofas (1765-1833)
- Ogonek, Elizabeth (b. 1989)
- Ogren, Jayce John (b.1979)
- Ogunboye, Paul
- Ogura, Miharu (b. 1996)
- Ogura, Ro (1916-90)
- Oh, Serin
- Ohana, Maurice (1913–92)
- Ohguri, Hiroshi (1918–82)
- Ohki, Masao (1901–71)
- Ohmae, Satoshi (b. 1943)
- Ohnaka, Megumi
- Ohrn, Konrad Mikal
- Ohzawa, Hisato (1907–53)
- Oisy, Huon d' (?-1191?)
- Oja, Eduard (1905–50)
- Ojeda, Ricardo
- Okano, Tei'ichi (1878–1941)
- Okatani, Kaori
- Okechukwu, Innocent
- Okkenhaug, Paul (1908–75)
- Okoye, Nkeiru
- Okpebholo, Shawn (b. 1981)
- Okunev, German Grigoriyevich (1931–73)
- Olafsson, Kent
- Olague, Bertolomeu de (b.1658)
- Olague, Martinho García de
- Olah, Tiberiu (1928–2002)
- Olaizola, Gabriel de (1883–1969)
- Olan, David (b. 1948)
- Olavide, Gonzalo de (1934-2005)
- Olaya, Pedro (1911-41)
- Olaya Muñoz, Jorge (1916-95)
- Olbrisch, Franz Martin (b.1952)
- Olcott, Chauncy (1858-1932)
- Olczak, Krzysztof (b.1956)
- Oldberg, Arne (1874-1962)
- Oldfield, Mike (b.1953)
- Oldham, Arthur William (1926–2003)
- Oldham, Kevin William (1960–93)
- Olechowski, Józef (b.1959)
- Olenchik, Iwan Fedorowich (b. 1952)
- Olesen, Thomas Agerfeldt (b.1969)
- Oley, Johann Christoph (1738–89)
- Olias, Lotar (1913-90)
- Oliva, Julio César (b.1947)
- Oliva, Marcos (b.1964)
- Oliva, Michael (b.1965)
- Olivadoti, Joseph (1893-1977)
- Oliveira, João Pedro (b.1959)
- Oliveira, Manuel de Botelho (1636-1718)
- Oliver
- Oliver, Barnaby
- Oliver, Benjamin (b.1981)
- Oliver, Des
- Oliver, Harold (b.1942)
- Oliver, John (b. 1959)
- Oliver, Stephen (1950–92)
- Oliver La Rosa, Jaime E
- Oliverio, James
- Olivero, Betty (b.1954)
- Olivero, Edgar (b. 1985)
- Oliveros, Pauline (1932–2016)
- Olivers, Thomas (1725-99)
- Olivia, Julio César (b.1947)
- Olivier, Johannes
- Olivieri, Dino (1905–63)
- Olivieri, Mark
- Oliviero, Nino (1918-80)
- Ollén, Bengt (b. 1950)
- Olli, Kalevi (b.1951)
- Ollone, Max d' (1875–1959)
- Olm, Marcel (b.1937)
- Olman, Abe (1887-1984)
- Olmeda, Federico (1865–1909)
- Olmo, Walter (1938-2019)
- Olofsson, Kent (b.1962)
- Olofsson, Olov
- Olrog, Ulf Peder (1919–72)
Composers: Olsen - Orozco
- Olsen, (Carl Gustav) Sparre (1903–84)
- Olsen, Arne Rodvelt (b.1949)
- Olsen, Carl Gustav Sparre (1903–84)
- Olsen, James (b.1982)
- Olsen, Lance Austin (b.1943)
- Olsen, Michael Peter (b. 1974)
- Olsen, Morten (b.1961)
- Olsen, Ole (1850–1927)
- Olsen, Poul Rovsing (1922–82)
- Olshanetsky, Alexander (1891–1946)
- Olson, Kevin (b.1970)
- Olson, Lars Jergen (b.1958)
- Olson, Tawnie (b. 1974)
- Olsson, Otto Emanuel (1879–1964)
- Olsson, Pers Erik (b.1942)
- Olsson-Follinger, Goran (1886-1969)
- Olsvay, Endre (b.1961)
- Olthuis, Kees (1940–2019)
- Oltra, Manuel (1922–2015)
- Omelchuk, Oxana (b.1975)
- Omizzolo, Silvio (1905-91)
- Onaka, Megumi (b.1924)
- Oncley, Alma (1904-2003)
- Ondříček, František (1857–1922)
- Onna, Peter van (b.1966)
- Ono, Kaoli
- Ono, Tadasuke (1895–1929)
- Ono, Yoko (b.1933)
- Onofre, Marcilio (b.1982)
- Onofri, Enrico (b.1967)
- Onovwerosuoke, Fred (b. 1960)
- Onslow, Georges (1784–1853)
- Onyeji, Christian
- Oortmerssen, Jacques van (1950–2015)
- Oosten, Roel van (b.1958)
- Opalka, Tomasz (b. 1983)
- Opel, Doug (b.1967)
- Openshaw, John
- Opilionis de Jawor, Othmarus (fl.1440)
- Opitiis, Benedictus de
- Oppel, Reinhard (1878–1941)
- Oppenheim, Henri
- Opperman, Kalmen (1919-2010)
- Oquin, Wayne (b.1977)
- Oradini, Giovan Battista (18th century)
- Oram, Celeste (b. 1990)
- Orbán, György (b.1947)
- Orbelian, Konstantin (1928-2014)
- Orbit, William (b.1956)
- Orbón, Julián (1925–91)
- Ord, Boris (1897-1961)
- Ordonez, Karl von (1734–86)
- Ordway, Scott (b.1984)
- Ore, Cecilie (b.1954)
- Orefice, Giacomo (1865–1929)
- Orejon y Aparicio, Jose de (b.1705)
- Orekhov, Sergei (1935-98)
- Orem, Preston Ware (1865-1938)
- Orendain, Mauricio Silva (b. 1992)
- Oreni, Paolo (b.1979)
- Orešic, Urška
- Orfe, John
- Orff, Carl (1895–1982)
- Orgas, Annibale (c.1585-1629)
- Oriola, Pere (fl.1440-84)
- Oriwoh, Edewede (b. 1981)
- Orkin, Evgeny (b.1977)
- Orlamunder, Johann (d. 1889)
- Orlandini, Giovanni Maria (1675–1760)
- Orlando, Stéphane
- Orléans, Hilaire d'
- Orléans, Mercure d' (fl.c.1590-1619)
- Orlinski, Heinz Bernhard (1928-2012)
- Orlovich, Matthew (b.1970)
- Orme, Robert (d.1711)
- Orning, Tanja (b.1967)
- Ornstein, Leo (1892–2002)
- Orologio, Alessandro (1550–1633)
- Oropeza Volcán, Pedro (1872-1959)
- Orozco, Fabio Salazar
Composers: Orozco - Otterloo
- Orozco, Keyla (b.1973)
- Orr, Buxton (1924–97)
- Orr, Charles Wilfred (1893–1976)
- Orr, Robin (1909–2006)
- Orrego-Salas, Juan Antonio (1919–2019)
- Orschler, Johann Georg (1698-1767/70)
- Orshansky, Raisa
- Ortega, Juan (fl.c.1560)
- Ortega, Miquel (b. 1963)
- Ortelli, Antonio 'Toni' (1904-2000)
- Ortells, Antonio Teodoro (1647-1706)
- Orth, Rene
- Orthel, Léon (1905–85)
- Ortiz, Alfredo Rolando (b.1946)
- Ortiz, Carlos Vieco (1900-79)
- Ortiz, Diego (1510–70)
- Ortíz, Gabriela (b.1964)
- Ortiz, Pablo (b.1956)
- Ortiz-Alvarado, William (b.1947)
- Ortmans, René (1863-1949)
- Orto, Marbrianus de (1460–1529)
- Ortolani, Riziero 'Riz' (1926-2014)
- Ortolano, Nunzio (b. 1967)
- Orton, Richard (1940-2013)
- Orts, Jordi (b.1962)
- Orts, José Antonio (b. 1955)
- Osbon, David
- Osborn, Ed (b. 1964)
- Osborn, Laurence (b.1989)
- Osborn, Sean (b.1966)
- Osborne, George Alexander (1806–93)
- Osborne, Leslie (1905-90)
- Osborne, Nigel (b.1948)
- Osborne, Thomas (b.1978)
- Osborne, Tony (b.1947)
- Osborne, William (b.1951)
- Osborne, Willson (1906–79)
- Oscher, Efrain (b.1974)
- Oser, Stefan (b.1965)
- Osgood, Clive
- Oshima, Michiru (b.1961)
- Osiander, Lucas (1534–1604)
- Osipov, Nikolay Vasilevich
- Oskar Gottlieb, Oskar Gottlieb (b.1934)
- Osmon, Leroy (b.1948)
- Osorio, Daniel (b. 1971)
- Ospald, Klaus (b.1956)
- Ospina, Nicolás
- Ospital, Thomas (b.1990)
- Osser, Abe (Glenn) (1914-2014)
- Ossewaarde, Jack H (1918-2004)
- Ost, Jon-Eric
- Ostafew, Helen
- Osten-Sacken, Maximilian d'
- Ostendorf, Jens-Peter (1944–2006)
- Osterfield, Paul (b.1973)
- Ostermann, Oliver
- Ostojić, Lazar (b.1959)
- Ostrčil, Otakar (1879–1935)
- Ostrowski, Tomasz (b.1975)
- Ostrzyga, Michael (b.1975)
- Oswald, Andreas (1634-65)
- Oswald, Henrique (1852–1931)
- Oswald, James (1710–95)
- Oswald, John (b.1953)
- Otaka, Atsutada (b.1944)
- Otaño, José Maria Nemesio (1880–1956)
- Oteo, Alfonso Esparza (1894–1950)
- Otero, Fernando (b. 1972)
- Othegraven, August von (1864-1946)
- Othmayr, Kaspar (1515–53)
- Ott, Alice Sara (b.1988)
- Ott, Daniel (b.1960)
- Ott, David (b.1947)
- Ott, Hans Jakob (1715-69)
- Otte, Erik (b.1955)
- Otte, Hans (1926–2007)
- Ottensamer, Daniel (b.1986)
- Otterloo, Rogier van (1941-88)
- Otterloo, Willem van (1907–78)
Composers: Ottman - Ozone
- Ottman, John (b.1964)
- Otto, Hans (1922-96)
- Otto, Johann
- Otto, Luigi (c.1750-?)
- Otto, Stephan (1594–1656)
- Otto, Valerius (1579-1612)
- Ouellette, Antoine (b. 1960)
- Ourkouzounov, Atanas (b.1970)
- Ouseley, Frederick Arthur Gore (1825–89)
- Ouzounoff, Alexandre (b. 1955)
- Ovalle, Jaime (1894–1955)
- Ovalle, Rafael Álvarez (1858-1946)
- Ovchinnikov, Vladimir Pavlovich (b.1958)
- Overhead, Christian (b. 1989)
- Overoye, Odd Johan (b.1961)
- Overton, David
- Overton, Hall (1920-72)
- Owen, David (1709-39)
- Owen, Jerry M
- Owen, Morfydd (1891-1918)
- Owen, Morfydd Llwyn (1891-1918)
- Owen, Richard (b.1922)
- Owen, William (1814-93)
- Owens, Harry (1902-86)
- Owens, Matthew (b.1971)
- Owens, Robert (1925–2017)
- Oxinaga, Joaquin (1719–89)
- Oxley, Harrison (1933-2009)
- Oyanadel, Mario
- Oysher, Moishe (1906-58)
- Ozi, Etienne (1754-1813)
- Ozipko, Jerry
- Ozone, Makoto (b. 1961)
