| O2 Films | — | — | 3 |
| O3 Medya | — | — | 1 |
| Oakhurst Productions | — | — | 2 |
| Oakshire Productions | — | — | 1 |
| Oberon Cinematogràfica | Barcelona | 1990 | 1 |
| Oberon Media | Kota New York | 2003 | 2 |
| Ocean Entertainment | Halifax | — | — |
| Oceania Produzioni Internazionali Cinematografiche | — | — | 1 |
| Oceanic Preservation Society | Colorado | 2005 | 1 |
| OCS | — | 7 Januari 1991 | 1 |
| OddLot Entertainment | Culver City | 2001 | 1 |
| Odeon | — | — | 1 |
| Odesa Film Studio | Odesa | 1919 | 128 |
| Odessa Filmworks | Ottawa | — | 1 |
| Office de Radiodiffusion Télévision Française | Paris | 1964 | 3 |
| Official Credit Institute | Paseo del Prado | 1962 | 3 |
| OffSide | Roma | — | 2 |
| Okko | Sankt-Peterburg | 2011 | 1 |
| Okko Production | Praha | — | 1 |
| OLM (studio) | Setagaya | Juni 1994 | 31 |
| Om Films | Santa Monica | 2006 | — |
| Ombetja Yehinga Organisation | Windhoek-Prosperita | 2001 | 1 |
| Omnia Film | Munich | — | 1 |
| Omroep MAX | Hilversum | 2002 | 1 |
| On the Day Productions | — | — | 3 |
| One Astor Plaza | — | 1972 | 1 |
| ONE Championship | Kallang | 14 Juli 2011 | 1 |
| One Hundred Years of Film | Hong Kong | 1999 | 14 |
| One Race Films | Studio City | 1995 | 8 |
| One's Youth | — | 2015 | — |
| Onyx Collective | — | 17 Mei 2021 | — |
| Open de España | — | 1912 | 1 |
| Optimystix Entertainment | Mumbai | 2000 | 1 |
| Orang Het | — | 1700 SM | 1 |
| Orange Cinéma Séries | Paris | 13 November 2008 | 1 |
| Orange S.A. | Issy-les-Moulineaux | 1988 | 1 |
| Orange Studio | Paris | 2007 | 20 |
| Orange Studio | Issy-les-Moulineaux | 22 Oktober 2001 | 1 |
| ORF | Wina | 19 Mei 1953 | 11 |
| Oria Films | Madrid | 1999 | 4 |
| Oriental DreamWorks | Xuhui District | 6 Agustus 2012 | 3 |
| Oriental Film | Batavia | 1940 | 1 |
| Origin Pictures | — | 2008 | 2 |
| Orion Pictures | Los Angeles | 1978 | 87 |
| Orisono | Luzern | 2020 | 1 |
| Orlando Film Festival | — | 2005 | 1 |
| Orona/Stevens | — | — | 1 |
| Oscar Film | — | — | 18 |
| Oslo Talefilm | Oslo | — | 3 |
| Ostankino | Moskow, Ostankino Technical Center | 27 Desember 1991 | — |
| Ostdeutscher Rundfunk Brandenburg | Babelsberg | 12 Oktober 1991 | 2 |
| Ostlicht Filmproduktion | Weimar | 2009 | 2 |
| Otomatic | — | — | 1 |
| Ouille Productions | Neuilly-sur-Seine | 1996 | 1 |
| Outlaw Productions | — | — | 8 |
| Outre-Mer 1ère | Malakoff | 14 September 1954 | 1 |
| Outside Films | — | — | 1 |
| Outspoken Media | Kota New York | 2004 | 1 |
| Owj Arts and Media Organization | Teheran | 2011 | 5 |
| Oxford Films | — | — | 1 |
| Oxford Scientific Films | London | 1968 | — |
| OXYBOT | — | Desember 2004 | 1 |
| OÜ Polarfilm | Tallinn | 1998 | — |
| Õ-Fraktsioon | Tallinn | 14 Mei 2003 | 1 |
| Ö-Filmproduktion Löprich & Schlösser | Berlin | — | 2 |