| Ocean Desolation (2024) | 4,772 | 16 |
| Ocean Drive Challenge (2012) | 5,563 | 19 |
| The Ocean Hunter (1998) | 2,185,365 | 249 |
| Ocean Is Home : Island Life Simulator (2022) | 2,825,198 | 180 |
| Ocean Keeper: Dome Survival (2024) | 61,485 | 88 |
| Ocean Man (2023) | 2,063,567 | 122 |
| Ocean Planet (2024) | 125,484 | 32 |
| Ocean Punk (2023) | 232 | 4 |
| Ocean Trader (1995) | 3,079 | 6 |
| Ocean's Heart (2021) | 1,981,606 | 2,031 |
| Oceanarium World (2024) | 1,259 | 1 |
| Oceancatch (2022) | 0 | 0 |
| OceanCraft (2021) | 3,701,680 | 97 |
| Oceanhorn 2: Knights of the Lost Realm (2019) | 19,415,379 | 4,413 |
| Oceanhorn: Chronos Dungeon (2021) | 110,760 | 246 |
| Oceanhorn: Monster of Uncharted Seas (2013) | 26,903,788 | 9,219 |
| Oceanwork (2021) | 295,400 | 84 |
| 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) | 537,452 | 220 |
| 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) | 362,040,387 | 4,965 |
| Octodad: Dadliest Catch (2014) | 420,135,083 | 12,004 |
| OctoFurry (2020) | 3,393 | 3 |
| Octogeddon (2018) | 292,499,328 | 1,456 |
| Octomania (2007) | 30,755 | 61 |
| OctoMaze (2022) | 3,635 | 34 |
| Octopath Traveler (2018) | 152,179,914 | 91,154 |
| Octopath Traveler II (2023) | 48,017,684 | 58,388 |
| Octopath Traveler: Champions of the Continent (2020) | 14,932,797 | 9,761 |
| 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) | 1,879,313 | 1,190 |
| Odama (2006) | 652,678 | 180 |
| Odania Sports Arena (2022) | 0 | 0 |
| Odd Realm (2019) | 1,542,559 | 426 |
| Odd Remedy (2024) | 929,449 | 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) | 3,490,351 | 2,943 |
| Oddsparks: An Automation Adventure (2024) | 2,137,359 | 1,965 |
| Oddventure (2022) | 177,289 | 135 |
| Oddworld Adventures (1998) | 75,773 | 145 |
| Oddworld: Abe's Exoddus (1998) | 12,430,914 | 5,807 |
| Oddworld: Abe's Oddysee (1997) | 36,731,765 | 8,460 |
| Oddworld: Munch's Oddysee (2001) | 8,660,602 | 2,450 |
| Oddworld: New 'n' Tasty! (2016) | 27,029,405 | 9,825 |
| Oddworld: Soulstorm (2021) | 68,697,208 | 15,524 |
| Oddworld: Stranger's Wrath (2005) | 16,931,921 | 5,903 |
| Oddyssey: Your Space, Your Way (2023) | 340,555 | 111 |
| Odell Lake (1986) | 79,013 | 31 |
| Odin Sphere (2007) | 6,886,691 | 7,478 |
| Odin Sphere Leifthrasir (2016) | 10,764,350 | 19,964 |
| Odium (2022) | 130,151 | 81 |
| Odysseus Kosmos and his Robot Quest (2018) | 247,124 | 146 |
| Odyssey - The Story of Science (2017) | 1,868 | 10 |
| Odyssey of Dremid'ir (2024) | 27 | 3 |
| The Odyssey of the Mammoth (2022) | 1,173,811 | 251 |
| Odyssey: The Compleat Apventure (1980) | 9,231 | 5 |
