| Ocean Desolation (2024) | 4,772 | 16 |
| Ocean Drive Challenge (2012) | 5,563 | 19 |
| The Ocean Hunter (1998) | 2,188,080 | 250 |
| Ocean Is Home : Island Life Simulator (2022) | 2,825,736 | 181 |
| Ocean Keeper: Dome Survival (2024) | 61,815 | 95 |
| Ocean Man (2023) | 2,063,671 | 124 |
| Ocean Planet (2024) | 125,484 | 32 |
| Ocean Punk (2023) | 324 | 5 |
| Ocean Trader (1995) | 3,079 | 6 |
| Ocean's Heart (2021) | 1,982,202 | 2,042 |
| Oceanarium World (2024) | 1,259 | 1 |
| Oceancatch (2022) | 0 | 0 |
| OceanCraft (2021) | 3,701,680 | 97 |
| Oceanhorn 2: Knights of the Lost Realm (2019) | 19,421,012 | 4,445 |
| Oceanhorn: Chronos Dungeon (2021) | 264,560 | 321 |
| Oceanhorn: Monster of Uncharted Seas (2013) | 26,909,915 | 9,323 |
| Oceanwork (2021) | 295,490 | 85 |
| Ocelot Sunrise (2023) | 17,813 | 40 |
| Ochitsubaki (2021) | 78 | 2 |
| Ocnus Theory (2023) | 464 | 14 |
| OCO (2021) | 326,706 | 105 |
| OctaFight (2020) | 2,619,301 | 62 |
| Octagon (2013) | 556,151 | 224 |
| Octahedron (2018) | 972,570 | 211 |
| Octane Remix (2023) | 457 | 14 |
| Octapolis (1987) | 9,043 | 11 |
| Octavio Camacho (2023) | 0 | 0 |
| Octo Vinctum: Saga of the Galactic Stardom War (2022) | 0 | 0 |
| Octo's Balloon Challenge (2024) | 553 | 2 |
| October Night Games (2020) | 265,260 | 38 |
| Octodad (2010) | 362,043,582 | 4,980 |
| Octodad: Dadliest Catch (2014) | 420,173,521 | 12,060 |
| OctoFurry (2020) | 3,393 | 3 |
| Octogeddon (2018) | 292,611,730 | 1,459 |
| Octomania (2007) | 30,755 | 61 |
| OctoMaze (2022) | 3,635 | 34 |
| Octopath Traveler (2018) | 155,048,127 | 92,116 |
| Octopath Traveler II (2023) | 48,485,811 | 59,586 |
| Octopath Traveler: Champions of the Continent (2020) | 15,029,908 | 9,999 |
| Octopede (2011) | 169 | 1 |
| OCTOPTICOM (2018) | 1,404 | 27 |
| Octopus City Blues (2025) | 7,825 | 40 |
| Ocular Deprivation (2022) | 124 | 7 |
| Oda Nobunaga Den (1998) | 128,373 | 260 |
| Odallus: The Dark Call (2015) | 1,880,106 | 1,196 |
| Odama (2006) | 653,007 | 183 |
| Odania Sports Arena (2022) | 0 | 0 |
| Odd Realm (2019) | 1,543,157 | 428 |
| Odd Remedy (2024) | 933,042 | 18 |
| Odd Sequence (2024) | 312 | 2 |
| ODDADA (2024) | 24,671 | 46 |
| Oddballz (1996) | 28,672 | 15 |
| Oddinary Highway (2021) | 299 | 9 |
| Oddity Girls: Virtual World (2020) | 1,068 | 9 |
| Oddly Enough: Pied Piper (2011) | 9,817 | 9 |
| Oddmar (2018) | 3,490,934 | 2,980 |
| Oddsparks: An Automation Adventure (2024) | 2,172,083 | 2,257 |
| Oddventure (2022) | 177,332 | 137 |
| Oddworld Adventures (1998) | 75,773 | 145 |
| Oddworld: Abe's Exoddus (1998) | 12,559,678 | 5,906 |
| Oddworld: Abe's Oddysee (1997) | 36,773,160 | 8,628 |
| Oddworld: Munch's Oddysee (2001) | 8,671,706 | 2,472 |
| Oddworld: New 'n' Tasty! (2016) | 27,039,385 | 9,898 |
| Oddworld: Soulstorm (2021) | 68,703,903 | 15,607 |
| Oddworld: Stranger's Wrath (2005) | 16,958,223 | 5,952 |
| Oddyssey: Your Space, Your Way (2023) | 340,555 | 111 |
| Odell Lake (1986) | 79,013 | 31 |
| Odin Sphere (2007) | 6,889,883 | 7,518 |
| Odin Sphere Leifthrasir (2016) | 10,767,282 | 20,110 |
| Odium (2022) | 130,152 | 81 |
| Odysseus Kosmos and his Robot Quest (2018) | 247,125 | 146 |
| Odyssey - The Story of Science (2017) | 1,868 | 10 |
| Odyssey of Dremid'ir (2024) | 27 | 3 |
| The Odyssey of the Mammoth (2022) | 1,173,898 | 252 |
| Odyssey: The Compleat Apventure (1980) | 9,234 | 6 |
