| | Oba-Oba | 1980 | Taito do Brasil | obaoba | | 0.00 |
| | Oba-Oba (alternate set) (clone of: obaoba) | 1980 | Taito do Brasil | obaoba1 | | 0.00 |
| | Octopus (Nova) (MPU4) | 1969 | Nova | m4octo | | 0.00 |
| | Odds On (Barcrest) (MPU3) | 1969 | Barcrest | m3oddson | | 0.00 |
| | Odeon Twister 2 (v202.19) | 1999 | CD Express | odeontw2 | | 0.00 |
| | Odin De Luxe | 1985 | Sonic | odin_dlx | | 0.00 |
| | Odisea Paris-Dakar | 1987 | Peyper | odisea | | 0.00 |
 | Oedo Fight (Japan Bloodshed Ver.) (clone of: bloodwar) | 1994 | Kaneko | oedfight | | 0.00 |
 | Off Road Challenge (v1.10) (clone of: offroadc) | 1997 | Midway | offroadc1 | | 0.00 |
| Off Road Challenge (v1.30) (clone of: offroadc) | 1997 | Midway | offroadc3 | | 0.00 |
| Off Road Challenge (v1.40) (clone of: offroadc) | 1997 | Midway | offroadc4 | | 0.00 |
| Off Road Challenge (v1.50) (clone of: offroadc) | 1997 | Midway | offroadc5 | | 0.00 |
| Off Road Challenge (v1.63) | 1997 | Midway | offroadc | Driving / Race (chase view) | 9.00 |
| | Off The Charts (Russia) | 1969 | WMS | otchart | | 0.00 |
 | Off the Wall (2-player cocktail) (clone of: offtwall) | 1991 | Atari Games | offtwallc | | 0.00 |
| Off the Wall (2/3-player upright) | 1991 | Atari Games | offtwall | Breakout | 5.00 |
 | Off the Wall (Sente) | 1984 | Bally/Sente | otwalls | Sports / Tennis | 6.00 |
| | Off Your Face (Bellfruit) (Scorpion 4) (set 1) | 1969 | BFM | sc4oyf | | 0.00 |
| | Off Your Face (Bellfruit) (Scorpion 4) (set 2) (clone of: sc4oyf) | 1969 | BFM | sc4oyfa | | 0.00 |
| | Office Yeo In Cheon Ha (version 1.2) | 2001 | Danbi | officeye | | 0.00 |
