| Ocean Desolation (2024) | 4,796 | 17 |
| Ocean Drive Challenge (2012) | 5,563 | 19 |
| The Ocean Hunter (1998) | 2,195,525 | 261 |
| Ocean Is Home : Island Life Simulator (2022) | 2,826,325 | 181 |
| Ocean Keeper: Dome Survival (2024) | 63,298 | 105 |
| Ocean Man (2023) | 2,067,738 | 129 |
| Ocean Planet (2024) | 468,187 | 35 |
| Ocean Punk (2023) | 324 | 5 |
| Ocean Trader (1995) | 3,079 | 6 |
| Ocean's Heart (2021) | 1,987,305 | 2,105 |
| Oceanarium World (2024) | 1,259 | 1 |
| Oceancatch (2022) | 0 | 0 |
| OceanCraft (2021) | 3,701,680 | 97 |
| Oceanhorn 2: Knights of the Lost Realm (2019) | 19,469,402 | 4,610 |
| Oceanhorn: Chronos Dungeon (2021) | 329,631 | 342 |
| Oceanhorn: Monster of Uncharted Seas (2013) | 26,992,321 | 9,460 |
| Oceanwork (2021) | 295,549 | 87 |
| Ocelot Sunrise (2023) | 17,813 | 40 |
| Ochitsubaki (2021) | 78 | 2 |
| Ocnus Theory (2023) | 464 | 14 |
| OCO (2021) | 334,100 | 109 |
| OctaFight (2020) | 2,619,301 | 62 |
| Octagon (2013) | 557,778 | 231 |
| 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) | 362,055,145 | 5,002 |
| Octodad: Dadliest Catch (2014) | 420,209,423 | 12,155 |
| OctoFurry (2020) | 3,393 | 3 |
| Octogeddon (2018) | 292,641,699 | 1,492 |
| Octomania (2007) | 30,755 | 61 |
| OctoMaze (2022) | 4,148 | 39 |
| Octopath Traveler (2018) | 165,159,506 | 101,528 |
| Octopath Traveler II (2023) | 49,901,328 | 62,001 |
| Octopath Traveler: Champions of the Continent (2020) | 15,773,579 | 10,364 |
| Octopede (2011) | 169 | 1 |
| OCTOPTICOM (2018) | 1,404 | 27 |
| Octopus City Blues (2025) | 7,826 | 41 |
| Ocular Deprivation (2022) | 124 | 7 |
| Oda Nobunaga Den (1998) | 128,373 | 260 |
| Odallus: The Dark Call (2015) | 1,883,929 | 1,208 |
| Odama (2006) | 666,943 | 191 |
| Odania Sports Arena (2022) | 164 | 5 |
| Odd Realm (2019) | 1,543,471 | 430 |
| Odd Remedy (2024) | 957,855 | 23 |
| Odd Sequence (2024) | 312 | 2 |
| ODDADA (2024) | 24,697 | 48 |
| Oddballz (1996) | 28,774 | 16 |
| Oddinary Highway (2021) | 299 | 9 |
| Oddity Girls: Virtual World (2020) | 1,068 | 9 |
| Oddly Enough: Pied Piper (2011) | 9,817 | 9 |
| Oddmar (2018) | 3,509,926 | 2,987 |
| Oddsparks: An Automation Adventure (2024) | 2,283,678 | 2,499 |
| Oddventure (2022) | 178,630 | 144 |
| Oddworld Adventures (1998) | 76,295 | 153 |
| Oddworld: Abe's Exoddus (1998) | 12,571,878 | 6,002 |
| Oddworld: Abe's Oddysee (1997) | 36,871,114 | 8,810 |
| Oddworld: Munch's Oddysee (2001) | 8,686,730 | 2,541 |
| Oddworld: New 'n' Tasty! (2016) | 27,054,056 | 9,973 |
| Oddworld: Soulstorm (2021) | 69,113,148 | 15,795 |
| Oddworld: Stranger's Wrath (2005) | 17,078,782 | 6,091 |
| Oddyssey: Your Space, Your Way (2023) | 340,556 | 111 |
| Odell Lake (1986) | 79,015 | 31 |
| Odin Sphere (2007) | 6,926,863 | 7,639 |
| Odin Sphere Leifthrasir (2016) | 10,771,533 | 20,353 |
| Odium (2022) | 130,316 | 81 |
| Odysseus Kosmos and his Robot Quest (2018) | 247,167 | 162 |
| Odyssey - The Story of Science (2017) | 1,868 | 10 |
| Odyssey of Dremid'ir (2024) | 27 | 3 |
| The Odyssey of the Mammoth (2022) | 1,174,123 | 258 |
| Odyssey: The Compleat Apventure (1980) | 9,440 | 6 |
