| Odyssey 1157 | WORLD | |
| Prototype |
| Oeka Kids - Anpanman no Hiragana Daisuki | JP | 1991-03-26 |
Bandai Namco | Commercial |
| Oeka Kids - Anpanman to Oekaki Shiyou!! | JP | 1990-10-25 |
Bandai Namco | Commercial |
| Oishinbo - Kyuukyoku no Menu Sanbon Shoubu | JP | 1989-07 |
Bandai | Commercial |
| Okkotoshi Puzzle - Tonjan! | JP | 1989-09-29 |
Jaleco | Commercial |
| Okkotoshi Puzzle - Tonjan! | JP | 1989-09-29 |
Jaleco | Prototype |
| Old Towers | WORLD | 2024-11 |
RetroSouls | Unlicensed |
| Old World | WORLD | |
| Prototype |
| Old World - Aftermath | WORLD | |
| Prototype |
| Old World - The Last Droid | WORLD | |
| Prototype |
| Oliver's Shell - An Adventure Story | WORLD | |
| Unlicensed |
| Olympic | AS | |
| Unlicensed |
| Olympic 2000 - 1000000-in-1 | AS | |
| Unlicensed |
| Olympic 2000 - 500-in-1 | TW | |
| Unlicensed |
| Olympic I.Q | KR | 1991 |
Sachen | Unlicensed |
| Olympic I.Q | TW | 1991 |
Sachen | Unlicensed |
| Olympus no Tatakai | JP | 1988-03 |
Brøderbund Software | Commercial |
| Omega Driver | WORLD | |
| Prototype |
| Once Upon a Time in China | WORLD | 2005 |
| Unlicensed |
| Oneshot | WORLD | |
| Prototype |
| Onyanko Town | JP | 1985-11-21 |
Pony Canyon | Commercial |
| Oof McBrewster's Haunted House Adventure | WORLD | 2020-11 |
Razzie.P | Unlicensed |
| Oopie's Quest | WORLD | |
| Unlicensed |
| Open Minded | WORLD | |
| Demo |
| Operation Secret Storm | US | 1991 |
Color Dreams | Unlicensed |
| Operation Wolf | EU | 1992 |
Taito | Commercial |
| Operation Wolf | JP | 1989-03-31 |
Taito | Commercial |
| Operation Wolf | US | 1989-05 |
Taito | Commercial |
| Oratorio | WORLD | 2022-09 |
John Vanderhoef | Demo |
| Orb-3D | US | 1990-10 |
HiTech Software | Commercial |
| Orebody - Binder's Tale | WORLD | 2022-12 |
Premium Edition Games | Demo |
| Orebody - Binder's Tale | WORLD | 2022-12 |
Premium Edition Games | Unlicensed |
| Orebody - Sand Ripples | WORLD | 2022-02 |
John Vanderhoef | Unlicensed |
| Os Cavaleiros do Zodiaco | AS | |
| Unlicensed |
| Osomatsu-kun - Back to the Me no Deppa no Maki | JP | 1989-12-08 |
Bandai | Commercial |
| Otaku no Seiza - An Adventure in the Otaku Galaxy | JP | 1991-07-31 |
M&M | Commercial |
| Othello | AU | 1986-11-13 |
Acclaim Entertainment | Unlicensed |
| Othello | JP | 1986-11-13 |
Acclaim Entertainment | Commercial |
| Othello | JP | 1986-11-13 |
Acclaim Entertainment | Prototype |
| Othello | TW | 1986-11-13 |
Kawada | Unlicensed |
| Othello | US | 1988-12 |
Acclaim Entertainment | Commercial |
| Oulu Zhi Zhan | CN | |
| Unlicensed |
| Ouroboros | WORLD | |
| Unlicensed |
| Outlanders | JP | 1987-12-04 |
Victor Entertainment | Commercial |
| Over Horizon | EU | 1992-09-13 |
Hot-B | Commercial |
| Over Horizon | JP | 1991-04-26 |
Hot-B | Commercial |
| Over Horizon - Fei Li Hangdao | AS | 1991-04 |
| Unlicensed |
| Overclocked | WORLD | |
| Unlicensed |
| Overlord | US | 1993-01 |
Virgin | Commercial |
| Overlord | US | 1993-01 |
Virgin Interactive | Prototype |
| P'Radikus Conflict | US | 1990 |
Color Dreams | Unlicensed |
| P.O.W. - Prisoners of War | EU | 1989-09 |
SNK | Commercial |
| P.O.W. - Prisoners of War | US | 1989-09 |
SNK | Commercial |
| PLOID | WORLD | 2020 |
Nape Games | Unlicensed |
| PR8 | WORLD | |
| Prototype |
| PR8 | WORLD | |
| Unlicensed |
| PROTO DERE .NES | WORLD | 2019-06 |
AppSir Games | Unlicensed |
| PROTO_1987_01_IT | WORLD | 2025 |
Pasqui industry | Prototype |
| Pac-Land | JP | 1985-11-21 |
Namco | Commercial |
| Pac-Land | WORLD | 1985-11-21 |
Namco | Commercial |
| Pac-Man | AS | 1984-11-02 |
| Unlicensed |
| Pac-Man | EU | 1993 |
Tengen | Commercial |
| Pac-Man | JP | 1984-11-02 |
Tengen | Commercial |
| Pac-Man | US | 1988-10 |
Namcot | Prototype |
| Pac-Man | US | 1988-10 |
Namcot | Unlicensed |
| Pac-Man | US | 1991 |
Namco | Commercial |
| Pac-Man | WORLD | 1984-11-02 |
Tengen | Commercial |
| Pac-Man - Championship Edition | EU | 1993 |
Bandai Namco Entertainment | Commercial |
| Pac-Man - Championship Edition | JP | 1984-11-02 |
Bandai Namco Entertainment | Commercial |
| Pac-Man - Championship Edition | US | 1988-10 |
Bandai Namco Entertainment | Commercial |
| Pac-Mania | US | 1991 |
Tengen | Unlicensed |
| Pachi-Slot Adventure 2 - Sorotta-kun no Pachi-Slot Tanteidan | JP | 1993-09 |
Coconuts Japan | Commercial |
| Pachi-Slot Adventure 3 - Bitaoshii 7 Kenzan! | JP | 1994-05-13 |
Coconuts Japan | Commercial |
| Pachicom | JP | 1985-11-21 |
Toshiba EMI | Commercial |
| Pachinko Daisakusen | JP | 1991-07-19 |
Coconuts Japan | Commercial |
| Pachinko Daisakusen 2 | JP | 1992-07-10 |
Coconuts Japan | Commercial |
| Pachio-kun 2 | JP | 1988 |
Coconuts Japan | Commercial |
| Pachio-kun 3 | JP | 1990-10-26 |
Coconuts Japan | Commercial |
| Pachio-kun 4 | JP | 1991-11-22 |
Coconuts Japan | Commercial |
| Pachio-kun 5 | JP | 1993-06-18 |
Coconuts Japan | Commercial |
| Packey | WORLD | 2025-03 |
TurtleRescueNES | Demo |
| Paco - New Frontiers | WORLD | |
| Demo |
| Paco The Alpaca | WORLD | |
| Demo |
| Pajama Hero - Nemo | JP | 1990-12 |
Capcom | Commercial |
| Pajama Hero - Nemo | JP | 1990-09 |
Capcom | Prototype |
| Palamedes | JP | 1990-07-06 |
Hot-B | Commercial |
| Palamedes | US | 1990-11 |
Hot-B | Commercial |
| Palamedes II - Star Twinkle, Hoshi no Mabataki | JP | 1991-05 |
Hot-B | Commercial |
| Panda Baby | CN | 1997 |
Dragon | Unlicensed |
| Panda World | TW | |
| Unlicensed |
| Panesian Power | WORLD | 2011 |
Bunnyboy | Unlicensed |
| Panic Restaurant | EU | 1994-05-26 |
Taito | Commercial |
| Panic Restaurant | US | 1992-10 |
Taito | Commercial |
| Panic! Dizzy | WORLD | 2019 |
Team Yolkfolk | Prototype |
| Paperboy | EU | 1990-10-26 |
Mindscape | Commercial |
| Paperboy | JP | 1991-01-30 |
Mindscape | Commercial |
| Paperboy | US | 1988-12 |
Mindscape | Commercial |
| Paperboy 2 | EU | 1992-06-06 |
Mindscape | Commercial |
| Paperboy 2 | US | 1992-04 |
Mindscape | Commercial |
| Papillon Gals | JP | 1990 |
Bunch Games | Unlicensed |