| 'O' Companies | Period (Timeline) | Item #: Game | Item #: Non-Game |
|---|---|---|---|
| O Donoghue, J.D. O [Brooklyn, NY, USA] | 1883 (1 year) | ||
| O&J Ent. [Korea] | 1999 (1 year) | ||
| O&T Soft | 1993 (1 year) | ||
| O'Meara, John U. [Washigton, DC, USA] | 1889 to 1890 (2 years) | ||
| O'Shaughnessy, Lawrence | 1991 (1 year) | ||
| O-Letto Novelty Co. | |||
| O-Shea, Kevin | 1986 (1 year) | ||
| O3 Ent. | 2004 to 2006 (3 years) | ||
| OAK [Japan] | 1982 to 1984 (3 years) | ||
| Oak Computers | 1988 (1 year) | ||
| Oak Mfg. Co., Inc. [Culver City, CA, USA] | 1947 to 1956 (10 years) | ||
| Oak Solutions | 1991 to 1994 (4 years) | ||
| Oakland Novelty Co. [Oakland, CA, USA] | 1902 (1 year) | ||
| Oakleaf | |||
| Oakley, Jason | 2000 (1 year) | ||
| Oakwood Publishing | |||
| OASE [Wolf Computertechnik] | 1990 to 1992 (3 years) | ||
| Oasis Soft. [England] | 1982 to 1985 (4 years) | ||
| OB Machine Co. [Portland, OR, USA] | 1927 (1 year) | ||
| OBA, Inc. [Dallas, TX, USA] | |||
| Oberheim | |||
| Oberlander [Fürth, Germany] | 1905 (1 year) | ||
| Oberth, Chris | 2021 (1 year) | ||
| Obic Business Consultants Co, Ltd. [Japan] | 1985 (1 year) | ||
| Obisoft | 1987 (1 year) | ||
| Objective Design, Inc. | 1977 to 1978 (2 years) | ||
| Obradovic, Dragoljub | 1988 (1 year) | ||
| Obrazovni Soft. | 1986 (1 year) | ||
| OBrien, Michael | 1990 (1 year) | ||
| Obsessed Maniacs, The | 1993 to 1995 (3 years) | ||
| Obunsha | 1995 (1 year) | ||
| OCC | 1996 (1 year) | ||
| Ocean Europe, Ltd. | 1991 to 1998 (8 years) | ||
| Ocean IQ | 1985 to 1986 (2 years) | ||
| Ocean Media | 2023 to 2024 (2 years) | ||
| Ocean of America, Inc. [San Jose, CA, USA] | 1990 to 1996 (7 years) | ||
| Ocean Soft., Ltd. [13156] | 1983 to 1999 (17 years) | ||
| Ocean State Publishing Corp. | 1995 (1 year) | ||
| Ocean Studios | 1990 (1 year) | ||
| Ochixn | 2016 to 2020 (5 years) | ||
| Ockers, Stan | 1977 (1 year) | ||
| OCS | 1988 (1 year) | ||
| Octagon Ent. [Japan] | |||
| OctagonSoft, Inc. | 1993 (1 year) | ||
| Octasoft | 1986 to 1987 (2 years) | ||
| Octavian Italy srl [Bussolengo, VR, Italy] | 2001 to 2010 (10 years) | ||
| Octek | 1990 to 1994 (5 years) | ||
| OCTOCOM | 2004 to 2009 (6 years) | ||
| Octocon Data | 1982 to 1983 (2 years) | ||
| Octree Soft. | 1988 to 1994 (7 years) | ||
| Odders Lab | 2023 (1 year) | ||
| Oddworld Inhabitants, Inc. | 2009 to 2022 (14 years) | ||
| Odesta Soft. | 1982 (1 year) | ||
| Odiesoft | 1988 to 1995 (8 years) | ||
| Odin Computer Graphics | 1985 to 1987 (3 years) | ||
| Odrex [Odessa, Ukraine] | |||
| Odyssey | 1991 to 1992 (2 years) | ||
| Odyssey Interactive | 2023 (1 year) | ||
| OEC [Omori Electric Co., Ltd.] [Japan] | 1979 to 1983 (5 years) | ||
| Oeil de Lynx, L' | 1984 (1 year) | ||
| OEM | 1983 (1 year) | ||
| OES Corp. | |||
| OFA [Paris, France] | |||
| Office Create [Japan] | 1994 to 2010 (17 years) | ||
| Office Koukan [Japan] | 1991 (1 year) | ||
| Officine Pixel | 2004 (1 year) | ||
| Ofites Informatica | 1984 (1 year) | ||
| OGA Co. [Japan] | 1974 (1 year) | ||
| Ogden & Co. [Chicago, IL, USA] | 1897 to 1901 (5 years) | ||
| Ogi, Y. | 1980 (1 year) | ||
| Oglesby, Mac | 1975 to 1977 (3 years) | ||
| Oguchin | 1992 (1 year) | ||
| Oh! Business | 1988 (1 year) | ||
| Oh!mz | 1986 (1 year) | ||
| Ohio Amusement Co. [Columbus, OH, USA] | 1944 (1 year) | ||
| Ohio Automatic Machine Co. [Cincinnati, OH, USA] | 1930 (1 year) | ||
| Ohio Match Co. [OH, USA] | |||
| Ohio Scientific, Inc. | 1977 to 1980 (4 years) | ||
| Ohio Specialty Co. [Cincinnati, OH, USA] | 1935 to 1949 (15 years) | ||
| Ohio Vending Machine Co. [Columbus, OH, USA] | 1930 to 1934 (5 years) | ||
| Ohira Giken Industry Co., Ltd. [Japan] | 1985 to 2005 (21 years) | ||
| OHMCO Inc. [New Mexico, USA] | |||
| Ohnishi, Hiroshi | 1982 (1 year) | ||
| OIC | |||
| OIC Co. [Chicago,. IL, USA] | 1916 (1 year) | ||
| Oizumi | 2001 to 2017 (17 years) | ||
| Oizumi Amuzio [Japan] | 2017 to 2024 (8 years) | ||
| OK [Japan] | 2014 to 2017 (4 years) | ||
| OK Corp. | 1985 (1 year) | ||
| OK Interactive [Korea] | 2000 to 2002 (3 years) | ||
| OK Marketing | 1993 (1 year) | ||
| OK Mfg. [Salt Lake City, UT, USA] | 2006 to 2007 (2 years) | ||
| Okapi | 1981 (1 year) | ||
| Okazaki Sangyo Co., Ltd. [Japan] | 1991 to 2012 (22 years) | ||
| Okidata | 1993 (1 year) | ||
| Oksan | 1992 (1 year) | ||
| Okta | 1987 (1 year) | ||
| Okumura [Japan] | 1972 to 2015 (44 years) | ||
| Okumura Yuki Co., Ltd. [Japan] | 2008 to 2011 (4 years) | ||
| Okumurayuuki Corp. [Japan] | 2011 (1 year) | ||
| Olakoa | 1989 (1 year) | ||
| Old Oak Den | 2018 to 2019 (2 years) | ||
| Olde N.Y. Amusement Factory [USA] | |||
| OlderGames | 2002 to 2007 (6 years) | ||
| Oldroyd & Gabryelski | 1980 (1 year) | ||
| Oleg Origin | 2016 (1 year) | ||
| Olipix | 2022 to 2024 (3 years) | ||
| Oliver, Thomas [Chicago, IL, USA] | 1908 (1 year) | ||
| Oliver, William S. [London, England] | 1887 (1 year) | ||
| OliverP | 2011 to 2016 (6 years) | ||
| Olivetti Prodest [Milan, Italy] | 1981 to 1990 (10 years) | ||
| Olsen Outdoors | 1991 (1 year) | ||
| Olsen, Dick | 1988 to 1995 (8 years) | ||
| Olsen, John | 1992 (1 year) | ||
| Olsen, Richard | 1988 to 1992 (5 years) | ||
| Olsen, Tyler | 1974 to 1975 (2 years) | ||
| Olsson, Magnus | 1990 to 2001 (12 years) | ||
| Olszewski, Ray | 1984 (1 year) | ||
| Olympia [France] | 1983 (1 year) | ||
| Olympia [Milan, Italy] | 1979 to 1983 (5 years) | ||
| Olympia Co., Ltd. [Japan] | 1993 to 2017 (25 years) | ||
| Olympia International | 1981 to 1985 (5 years) | ||
| Olympic Games Mfg. Co. | |||
| Olympic Video Gaming | 1989 (1 year) | ||
| Olympical | |||
| Olympus Electronics [Korea] | 1976 to 1977 (2 years) | ||
| OM Co., Ltd. | 1979 to 1980 (2 years) | ||
| Omage Micott, Inc. | 2000 (1 year) | ||
| Omega [Paris, France] | 1937 (1 year) | ||
| Omega Games | 1985 (1 year) | ||
| Omega Micott | 2000 to 2002 (3 years) | ||
| Omega Microware | 1981 to 1983 (3 years) | ||
| Omega Products [Carlsbad, CA, USA] | 1981 to 1982 (2 years) | ||
| Omega Project Co., Ltd. [Japan] | 2002 (1 year) | ||
| Omega Soft. | 1983 to 1986 (4 years) | ||
| Omega System | 1984 to 1999 (16 years) | ||
| Omen Soft. | 1984 (1 year) | ||
| Omikron | 1986 (1 year) | ||
| Omiya Soft | 1997 to 1998 (2 years) | ||
| OMK Soft. [Spain] | 1985 to 1990 (6 years) | ||
| Omni | 1980 to 1989 (10 years) | ||
| Omni Soft. | 1984 to 1985 (2 years) | ||
| Omnibyte | 1985 (1 year) | ||
| Omnik | 2000 (1 year) | ||
| Omnitrend | 1984 to 1987 (4 years) | ||
| Omnium | 1997 (1 year) | ||
| OMS [Office Management Systems AB] | 1983 (1 year) | ||
| On DiMand Co., Ltd. [Japan] | 1997 to 1998 (2 years) | ||
| ON Soft. [Norway] | 1989 (1 year) | ||
| On Three, Inc. | 1985 to 1987 (3 years) | ||
| On-Line Design, Inc. | |||
| On-line Ent., Ltd. | 1990 to 1995 (6 years) | ||
| On-Line Systems [USA] | 1980 to 1982 (3 years) | ||
| Onaki | 1986 (1 year) | ||
| Once Product | 1991 (1 year) | ||
| One Man Army Games | 2004 (1 year) | ||
| One or Eight | 2022 to 2024 (3 years) | ||
| One-Cent Amusement Co. [Camden, NJ, USA] | 1929 (1 year) | ||
| One-Use Toothbrush Corp. [Van Nuys, CA, USA] | |||
| OneTouch Technology, Ltd. | |||
| Oneway | 1988 to 1994 (7 years) | ||
| Ong Tat-Wee, David | 1994 (1 year) | ||
| Ongakukan | 1995 to 2001 (7 years) | ||
| Oni Records | 2000 (1 year) | ||
| Onion House [Japan] | 1994 (1 year) | ||
| Onion Soft | 1988 to 1993 (6 years) | ||
| Oniric Factor [Spain] | 2015 to 2017 (3 years) | ||
| Onko Electronics Co., Ltd. [Nagasaki, Japan] | 1982 (1 year) | ||
| OnLine [Russia] | 1992 (1 year) | ||
| Onoe Network | |||
| Onslaught | 1985 to 2018 (34 years) | ||
| Onslow Comtek | |||
| Ontañón, Santiago | 2016 to 2021 (6 years) | ||
| Onuma Denki Shoukai [Japan] | |||
| Onyx Systems | 1981 to 1982 (2 years) | ||
| Ookado Co., Ltd. [Japan] | 1984 (1 year) | ||
| Ookuroya | 1989 (1 year) | ||
| OOO Valnat | 2022 (1 year) | ||
| Oops [Japan] | 1987 (1 year) | ||
| OPC Soft. [Japan] | |||
| Opcode Games | 2003 to 2008 (6 years) | ||
| Opearlo | 2018 (1 year) | ||
| Opel | |||
| Open Book 9003 | 1996 (1 year) | ||
| Open Corp. | |||
| Open E&C [Korea] | 2003 (1 year) | ||
| Open Mind World [Korea] | 1999 to 2013 (15 years) | ||
| Open Production [Korea] | 1993 (1 year) | ||
| Open University, The | 1981 to 1984 (4 years) | ||
| Oper Coin, S.A. | 1988 to 1992 (5 years) | ||
| Oper-Video, S.A. | 2000 (1 year) | ||
| Opera Multimedia S.p.A. | 1995 (1 year) | ||
| Opera Soft. [Spain] | 1986 to 1991 (6 years) | ||
| Operamatic [Spain] | 1980 to 1981 (2 years) | ||
| Operations Research Office | 1953 to 1962 (10 years) | ||
| Operator's Piano Co. [Chicago, IL, USA] | 1920 (1 year) | ||
| Operators Guide | |||
| Operators Supply Co. | |||
| Operators Vending Machine Supply Co. [Los Angeles, CA, USA] | 1932 to 1939 (8 years) | ||
| Operomatic Video, S.A. | |||
| Opitz, Erich [Berlin, Germany] | 1939 (1 year) | ||
| Opium | 1995 (1 year) | ||
| OPlayer | |||
| OPM-Registers | 2020 (1 year) | ||
| Opportunities For Learning | |||
| Opt. 1 [Japan] | 1990 to 1992 (3 years) | ||
| OPTi | |||
| Optic Moon | 1993 (1 year) | ||
| Optima | 1983 (1 year) | ||
| Optimum Resource | 1982 to 1992 (11 years) | ||
| Optonica, Ltd. | 1994 to 1999 (6 years) | ||
| Optyk | 1992 (1 year) | ||
| Optyx Soft. | 1986 to 1987 (2 years) | ||
| Opus | 1983 (1 year) | ||
| Opus Ent., Ltd. [Surrey, England] | |||
| Ora Soft | 1995 to 1996 (2 years) | ||
| Oracion, Inc. [Japan] | 1996 to 1999 (4 years) | ||
| Orange Cherry | 1984 to 1991 (8 years) | ||
| Orange House [Japan] | 1989 to 1994 (6 years) | ||
| Orange Juice Soft. Systems | 1985 to 1986 (2 years) | ||
| Orange Micro | 1984 (1 year) | ||
| Orange Soft. | 1988 to 1989 (2 years) | ||
| OrangesofT [Korea] | 1996 to 2003 (8 years) | ||
| ORB [Japan] | 1993 (1 year) | ||
| Orb Gaming | 2018 (1 year) | ||
| Orb1tware | 1986 to 1988 (3 years) | ||
| Orbit | 1984 (1 year) | ||
| Orbit Electronics | |||
| Orbital Media | 2005 to 2006 (2 years) | ||
| Orbs | 1991 to 1992 (2 years) | ||
| Orbyte Soft. | |||
| Orca [Japan] | 2010 (1 year) | ||
| Orca Corp. [Japan] | 1981 to 1983 (3 years) | ||
| Ordia94 | 1985 (1 year) | ||
| Ordividuel | |||
| Oregan Dev. | 1992 (1 year) | ||
| Orel [Ukraine] | |||
| Orelec | 1976 (1 year) | ||
| Organic Soft. | 1981 (1 year) | ||
| Organised Solutions, Ltd. | 1988 (1 year) | ||
| Oric Enthusiast | |||
| Oric France | 1983 (1 year) | ||
| Oric International | 1984 (1 year) | ||
| Oric Owner Users Group | |||
| Oricsoft | |||
| Orient | |||
| Oriental Soft Japan | 2000 to 2002 (3 years) | ||
| Oriental Soft, Inc. | 2000 (1 year) | ||
| Origin Systems, Inc. [An Electronic Arts Co.] [17814] | 1983 to 1998 (16 years) | ||
| Origin, Oleg | 1997 to 2015 (19 years) | ||
| Original Amusements Co. [Southend-on-Sea, England] | 1930 (1 year) | ||
| Original Game | 1982 (1 year) | ||
| Original Machine Co. | |||
| Original Machine Mfgrs. [Southend, England] | 1932 to 1946 (15 years) | ||
| Orion [Portugal] | 1983 (1 year) | ||
| Orion Gaming | 2005 to 2010 (6 years) | ||
| Orion Micro Systems | 1989 (1 year) | ||
| Orion Soft. | 1982 to 1986 (5 years) | ||
| OrionSoft [France] | 2018 to 2024 (7 years) | ||
| Orkim Data | |||
| Orlitronic [France] | 1982 to 1984 (3 years) | ||
| Orms Mfg. Co. [Dallas, TX, USA] | 1956 (1 year) | ||
| Orphanware | 1986 to 1987 (2 years) | ||
| Orpheus | 1984 to 1986 (3 years) | ||
| Ortiz Gaming, S.L. | 2014 to 2015 (2 years) | ||
| Orwin, M. | 1981 to 1983 (3 years) | ||
| Oryx Gaming | |||
| OS Soft. | 1990 to 1994 (5 years) | ||
| Osaka Machine | 1974 (1 year) | ||
| Osaka Medical Computer [Japan] | 1983 (1 year) | ||
| Osaka Soft. | 1991 (1 year) | ||
| Osborne & Associates, Inc. | |||
| Osborne Computer Corp. | 1981 to 1984 (4 years) | ||
| Osbourne-McGraw Hill | 1983 to 1984 (2 years) | ||
| Osbrink Games Co. [Chicago, IL, USA] | 1934 (1 year) | ||
| Osbrink Mfg. Co., R.H. [Chicago, IL, USA] | 1933 to 1934 (2 years) | ||
| Oscar Soft. [Spain] | 1989 (1 year) | ||
| Osgood, Roger | 1992 (1 year) | ||
| Osmagyar Soft. | |||
| Osmosis Computer | 1982 to 1983 (2 years) | ||
| OSS | 1983 to 1986 (4 years) | ||
| Ostelbische Automaten | 1928 (1 year) | ||
| Ostjysk Automater | 1979 (1 year) | ||
| Otaboo | 2003 (1 year) | ||
| Other Ocean Interactive | 2015 to 2016 (2 years) | ||
| OTM | 1995 to 1996 (2 years) | ||
| Otomate [Japan] | 2018 (1 year) | ||
| Otomato [Paris, France] | 1936 (1 year) | ||
| Otrona | 1982 to 1983 (2 years) | ||
| Ottery, Darren | |||
| Otto & Sons, F.G. [Jersey City, NJ, USA] | 1898 to 1899 (2 years) | ||
| Otto Wichelhaus | 1930 (1 year) | ||
| Outer Limits | 1981 (1 year) | ||
| Outfit7, Ltd. | 2010 to 2018 (9 years) | ||
| Outlaw [Japan] | 1997 (1 year) | ||
| Outlet [UK] | 1987 to 1997 (11 years) | ||
| OutOfTheBit | 2023 (1 year) | ||
| Outou Shobou | 1996 (1 year) | ||
| Outrigger | 1995 to 1997 (3 years) | ||
| Outright Games | 2019 to 2024 (6 years) | ||
| Outsiders & NedoPC | 2019 (1 year) | ||
| Ouyou Densan Giken [Japan] | 1985 (1 year) | ||
| Oval Automation | 1986 (1 year) | ||
| Overlanders | 1989 to 2002 (14 years) | ||
| Overpriced Soft. | |||
| Overton Mfg. Co. [Topeka, KS, USA] | 1902 (1 year) | ||
| OVL | |||
| Owen, Andrew | 2002 to 2011 (10 years) | ||
| Owen, Simon | 2011 (1 year) | ||
| Owen, T.J. | 1983 (1 year) | ||
| Owl Soft. | 1985 (1 year) | ||
| Owlcat Games | 2023 (1 year) | ||
| Owlchemy Labs | 2023 (1 year) | ||
| Own-A-Phone | 1987 (1 year) | ||
| Oxford Computer Publishing | 1982 to 1985 (4 years) | ||
| Oxford Data | 1984 (1 year) | ||
| Oxford Radio Corp., The | 1930 (1 year) | ||
| Oxford Softworks | 1989 to 1999 (11 years) | ||
| OXiAB Game Studio | 2015 (1 year) | ||
| Oxxi | 1991 (1 year) | ||
| Oxygen | 1990 to 2003 (14 years) | ||
| Oxygen Games | 2003 to 2008 (6 years) | ||
| Oxygene | 2015 (1 year) | ||
| Oxyron | 1991 to 2012 (22 years) | ||
| Oy Hedengren, Ab | 1985 (1 year) | ||
| Oyhus, Kim G.S. | 1985 (1 year) | ||
| OZ Club | 1996 to 2000 (5 years) | ||
| OZ Corp. | |||
| Ozacq1, Inc. | 1999 (1 year) | ||
| Ozarka, Ron | |||
| Ozi Soft | 1984 to 1987 (4 years) | ||
| Ozzard | 1989 (1 year) | ||
| OzzyOuzo | 2020 (1 year) |