| O Entertainment | Burbank | 1990 | 3 |
| O2 Films | — | — | 3 |
| Oakshire Productions | — | — | 1 |
| Oberon Cinematogràfica | Barcelona | 1990 | 1 |
| Oberon Media | New York City | 2003 | 2 |
| Objectif 9 | — | — | 1 |
| OCS | — | January 7, 1991 | 1 |
| October Films | — | 1991 | 9 |
| OddLot Entertainment | Culver City | 2001 | 1 |
| Odesa Film Studio | Odesa | 1919 | 128 |
| Odessa Films | — | — | 5 |
| Odessa Filmworks | Ottawa | — | 1 |
| Odolttogi (Animation Studio) | — | April 1997 | 1 |
| Odyssey Entertainment | London | — | 1 |
| Office de Radio et Télévision des Comores | Moroni | December 14, 2015 | — |
| Official Credit Institute | Paseo del Prado | 1962 | 3 |
| OGN | Seoul | July 24, 2000 | — |
| Ognon Pictures | — | — | 3 |
| Ogun State Television | Abeokuta | 1981 | 2 |
| Okko | Saint Petersburg | 2011 | 1 |
| Okko Production | Prague | — | 1 |
| Om Films | Santa Monica | 2006 | — |
| Ombetja Yehinga Organisation | Windhoek-Prosperita | 2001 | 1 |
| Ombra Films | Barcelona | — | 3 |
| Omega Film & Television | Bromma | — | 3 |
| Omega Film GmbH | Berlin | — | 1 |
| Omnia Film | Munich | — | 1 |
| Omroep MAX | Hilversum | 2002 | 1 |
| One Astor Plaza | — | 1972 | 1 |
| ONE Championship | Kallang | July 14, 2011 | 1 |
| One Race Films | Studio City | 1995 | 8 |
| Onfilm | — | 1996 | 1 |
| Onyx Collective | — | May 17, 2021 | — |
| Optimystix Entertainment | Mumbai | 2000 | 1 |
| Opus Film | Łódź | 1991 | 4 |
| Orange | Issy-les-Moulineaux | 1988 | 1 |
| Orange Sky Golden Harvest | Middle Road | 1970 | 146 |
| Orange Studio | Paris | 2007 | 20 |
| Orange Television Network | — | 2005 | — |
| Oriental Film | Batavia | 1940 | 1 |
| Origin Animation | Beijing | July 14, 2010 | 1 |
| Origin Pictures | — | 2008 | 2 |
| Orion Classics | Los Angeles | 1982 | 1 |
| Orisono | Lucerne | 2020 | 1 |
| Ornis Films | — | 1969 | — |
| Orona/Stevens | — | — | 1 |
| Osakond | — | 2004 | 1 |
| Oscar Film | — | — | 18 |
| Oscilloscope | — | 2008 | 5 |
| Ostankino | Moscow, Ostankino Technical Center | December 27, 1991 | — |
| Ouille Productions | Neuilly-sur-Seine | 1996 | 1 |
| Outre-Mer 1ère | Malakoff | September 14, 1954 | 1 |
| Outspoken Media | New York City | 2004 | 1 |
| Owj Arts and Media Organization | Tehran | 2011 | 5 |
| Oxford Scientific Films | London | 1968 | — |
| OXYBOT | — | December 2004 | 1 |
| Oy Nordisk Film Ab | Helsinki | August 30, 1984 | 1 |
| OÜ Polarfilm | Tallinn | 1998 | — |
| Ö-Filmproduktion Löprich & Schlösser | Berlin | — | 2 |
| Österreichischer Rundfunk | Vienna | May 19, 1953 | 11 |
| Özen Film | — | — | 3 |