| name | games | status | region | founded | closed | activity | |
|---|
| Orpheus |
18 | | | | | 1984/1988 | |
| OSome Studio |
7 | active | | | | 2015/2018 | Website: http://osome-studio.com |
| OT Sports |
2 | | | | | 1997/1997 | |
| Otaku Publishing |
6 | | | 1998 | | 1996/1998 * | |
| Other Ocean Interactive |
16 | | | | | 2007/2015 | |
| OTM |
2 | | | | | 1995/1995 | |
| Otomate |
19 | | | | | 2009/2017 | |
| Otona no Douraku |
1 | | JP | | | 2013/2013 | Website: http://orenuma.h.fc2.com |
| Oubunsha |
6 | | | | | 1983/1983 | |
| Out of the Park Developments |
19 | | | | | 2006/2021 | |
| Outerlight |
3 | active | UK | 2002 | | 2006/2010 | HQ: Edinburgh, Scotland Website: http://www.outerlight.com |
| Outfit7 |
| | | | | | |
| Outhouse Software |
7 | | | | | 2001/2004 | |
| Outlaw Productions |
6 | | | | | 1988/1997 | |
| OutlawDuplicate |
2 | | | | | 1990/1990 | |
| Outlook Enterprises |
3 | | | | | 1986/1988 | |
| OutLook Entertainment |
2 | | | | | 2001/2002 | |
| OutOfTheBit |
| | | | | | |
| Outplay Entertainment |
2 | | | | | | |
| Outrage Entertainment |
6 | | | | | 1999/2003 | |
| Outrage Games |
3 | dead | | | 2004 | 1999/2002 | |
| Outrigger |
2 | | | | | 1995/1997 | |
| Outright Games |
39 | | | | | 2017/2024 | |
| Outspark |
4 | | | | | 2007/2010 | |
| Over the Top Games |
8 | active | ES | | | 2009/2019 | |
| OVERDRIVE |
9 | | | | | 2007/2013 | |
| Overflow |
5 | | | | | 2001/2015 | |
| OverGamez |
2 | | | | | 2020/2020 | |
| Overhaul Games |
6 | | | | | 2011/2019 | |
| Overhype Studios |
3 | | | | | 2017/2021 | |
| OVERKILL |
8 | active | SE | 2009 | | 2011/2016 | Founders: Ulf Andersson, Bo Andersson Subsidiary of Starbreeze since 2012 and … |
| Overmax Studio |
2 | | | | | 2000/2001 | |
| Overworks |
4 | dead | | | | 2000/2003 | Formerly known as AM7, later merged with Wow Entertainment to form Sega WOW. |
| Ovidiu Pop |
| | | | | | |
| Owlchemy Labs |
13 | | | | | 2011/2018 | |
| Oxeye Game Studio |
7 | active | SE | | | 2008/2016 | Website: http://www.oxeyegames.com |
| Oxford Computer Publishing |
3 | | | | | 1983/1984 | |
| Oxford Digital Enterprises |
37 | bought | UK | 1983 | 1993 | 1985/1993 | Bought in 1993 by Empire Interactive |
| Oxford Mobius |
8 | | | | | 1988/1998 | |
| Oxford Softworks |
31 | | | | | 1989/2000 | |
| OXiAB Game Studio |
3 | | | | | 2015/2019 | |
| OXXO Media |
3 | | | | | 2000/2001 | |
| Oxygen Interactive |
45 | | | | | 2002/2009 | |
| Oxygene Media |
2 | | | | | 2012/2016 | |
| Oyaji Games |
6 | | | | | 2009/2012 | |
| Oz Club |
8 | | | | | 1996/1999 | |
| Ozark Legacy |
1 | active | US | 1998 | | 1998/1998 | Label of MELDANNIC, LLC. A company founded by Dan Bunten's children to preserve … |
| Ozark Softscape |
19 | dead | US | 1983 | 1993 | 1983/2014 | Founded by Bill & Dan Bunten, Jim Rushing, & Alan Watson in Little Rock, AR kept … |
| OziSoft |
6 | | | | | 1983/1987 | |
