| O Entertainment | Burbank | 1990 | 3 |
| O2 Films | — | — | 3 |
| O3 Medya | — | — | 1 |
| Oakshire Productions | — | — | 1 |
| Oberon Cinematogràfica | Barcelona | 1990 | 1 |
| Oberon Media | New York City | 2003 | 2 |
| Objectif 9 | — | — | 1 |
| Objectiv Filmstudio | — | — | 1 |
| Ocean Entertainment | Halifax | — | — |
| Oceania Produzioni Internazionali Cinematografiche | — | — | 1 |
| Oceanic Preservation Society | Colorado | 2005 | 1 |
| OCN | — | 1995 | 6 |
| OCS | — | January 7, 1991 | 1 |
| October Films | — | 1991 | 9 |
| OddLot Entertainment | Culver City | 2001 | 1 |
| Odeon | — | — | 1 |
| Odesa Film Studio | Odesa | 1919 | 128 |
| Office de radiodiffusion télévision française | Paris | 1964 | 3 |
| OGN | Seoul | July 24, 2000 | — |
| Ognon Pictures | — | — | 3 |
| Ogun State Television | Abeokuta | 1981 | 2 |
| Oktober | Helsinki | June 4, 2004 | 2 |
| OLM, Inc. | Setagaya | June 1994 | 31 |
| Olympic | — | 1962 | 1 |
| Om Films | Santa Monica | 2006 | — |
| Ombra Films | Barcelona | — | 3 |
| Omega Film & Television | Bromma | — | 3 |
| Omnia Film | Munich | — | 1 |
| Omroep MAX | Hilversum | 2002 | 1 |
| One Cool Film Production Limited | — | 2013 | 3 |
| One Fine Day Films | Berlin | 2008 | 1 |
| One Race Films | Studio City | 1995 | 8 |
| ONO | Madrid | September 29, 1998 | 2 |
| Onyx Collective | — | May 17, 2021 | — |
| Open de España | — | 1912 | 1 |
| Optimystix Entertainment | Mumbai | 2000 | 1 |
| Orange | Issy-les-Moulineaux | 1988 | 1 |
| Orange Cinéma Séries | Paris | November 13, 2008 | 1 |
| Orange Studio | Paris | 2007 | 20 |
| Orange Studio | Issy-les-Moulineaux | October 22, 2001 | 1 |
| Orbis, Rhineland-Palatinate | — | — | 1 |
| Oria Films | Madrid | 1999 | 4 |
| Origin Pictures | — | 2008 | 2 |
| Original Productions | — | 1999 | — |
| Orlando Film Festival | — | 2005 | 1 |
| Ornis Films | — | 1969 | — |
| Oscar Film | — | — | 18 |
| Oscilloscope | — | 2008 | 5 |
| Oslo Talefilm | Oslo | — | 3 |
| Ostdeutscher Rundfunk Brandenburg | Babelsberg | October 12, 1991 | 2 |
| Ostlicht Filmproduktion | Weimar | 2009 | 2 |
| Otomatic | — | — | 1 |
| Ouille Productions | Neuilly-sur-Seine | 1996 | 1 |
| Outlaw Productions | — | — | 8 |
| Outspoken Media | New York City | 2004 | 1 |
| Overbrook Entertainment | Beverly Hills, Los Angeles | 1998 | 20 |
| Ovídeo TV | Barcelona | — | 3 |
| Owesen-film | — | — | 3 |
| Owj Arts and Media Organization | Tehran | 2011 | 5 |
| OÜ Polarfilm | Tallinn | 1998 | — |
| Ö-Filmproduktion Löprich & Schlösser | Berlin | — | 2 |