Video Games starting with O
- Obduction
- Object Ward
- Objects in Space
- Obscure
- Observation
- Observer
- Observer: System Redux
- Obsidian Legion
- Occupy White Walls
- Ocean Mirror
- Ocean's Heart
- Oceanarium
- Oceanfall
- OCO
- Octahedron
- Octodad
- Octodad 2
- Octodad: Dadliest Catch
- Octogeddon
- Octopath Traveler
- Octopath Traveler 2
- Octopus City Blues
- Oculus Go
- Oculus Rift DK2
- Oculus Touch
- OD
- Odd Realm
- ODDADA
- Oddworld: Abe's Exoddus
- Oddworld: Abe's Oddysee
- Oddworld: Munch's Oddysee
- Oddworld: New 'n' Tasty
- Oddworld: Soulstorm
- Oddworld: Stranger's Wrath HD
- Ode To A Moon
- Of Love And Eternity
- Of Orcs and Men
- OFF
- Off The Grid
- Off-Peak
- Offendron Warrior
- Offline
- Offworld Trading Company
- Offworld Trading Company - Market Corrections DLC
- Ogre
- Oh My Git!
- Oh My Godheads
- Oikospiel Book I
- Oil Rush
- OK/NORMAL
- Okami
- Okami HD
- Okhlos
- oknytt
- Old Friend
- Old Gods Rising
- Old Man's Journey
- Old School Musical
- Old School RuneScape
- Old Skies
- Old World
- Oligopoly
- Olija
- Ollie & Bollie
- Ollie-Oop
- OlliOlli
- OlliOlli 2: Welcome to Olliwood
- OlliOlli World
- Olorun: Theocracy
- Olympic Games Tokyo 2020
- Omensight
- Omerta - City Of Gangsters
- OMFG: One Million Fatal Guns
- Omikron: The Nomad Soul
- Omnibus
- Omno
- Omori
- OMSI
- OMSI 2
- Once, In Times Of Chaos
- Onde
- One Chance
- One Eyed Kutkh
- One Finger Death Punch
- One Finger Death Punch 2
- One Hand Clapping
- One Hour One Life
- One Night Stand
- One Punch Man World
- One Punch Man: A Hero Nobody Knows
- One-Eyed Likho
- OneShot
- Onimusha: Warlords
- Oninaki
- Onirism
- Only Up!
- Onrush
- Onsen Master
- Onward
- Ooblets
- Oona The Druid's Path
- Oort Online
- Open Roads
- OpenTTD
- Operation Citadel
- Operation Flashpoint
- Operation Flashpoint: Dragon Rising
- Operation Flashpoint: Red River
- Operation: Harsh Doorstep
- Operation: Tango
- Opus Magnum
- OPUS: Echo Of Starsong
- OPUS: Prism Peak
- OPUS: The Day We Found Earth
- Orange Island
- Orange Moon
- Orangeblood
- Orbi Universo
- Orbitals
- OrbLands
- Orbo's Odyssey
- Orchids to Dusk
- Orcs Must Die!
- Orcs Must Die! 2
- Orcs Must Die! 3
- Orcs Must Die! Unchained
- Order of Battle: World War II
- Order of Magnitude
- Order of War
- Ori and the Blind Forest
- Ori and the Blind Forest: Definitive Edition
- Ori and the Will of the Wisps
- Origin
- Orion: Dino Beatdown
- Orphan Age
- Orten Was The Case
- Orwell
- Orwell: Ignorance Is Strength
- Orwell's Animal Farm
- ORX
- OshiRabu: Waifus Over Husbandos
- Osiris: New Dawn
- osmos
- Ostranauts
- Ostriv
- Othercide
- OU
- Our Darker Purpose
- Out of Ammo
- Out Of Hands
- Out of the Park Baseball
- Out of the Park Baseball 17
- Out of the Park Baseball 18
- Out of the Park Baseball 20
- Out There: Oceans of Time
- Out There: Ω Edition
- Outbound
- Outbuddies
- Outcast
- Outcast - Second Contact
- Outcast 1.1
- Outcast 2: A New Beginning
- Outer Wilds
- Outerverse
- Outland
- Outlanders
- Outlast
- Outlast 2
- Outlaws
- Outpath
- Outpath: First Journey
- Outpost (Open Mid Interactive)
- Outpost: Infinity Siege
- Outreach
- Outriders
- Outriders Worldslayer
- Outward
- Over Jump Rally
- Over My Dead Body (For You)
- Over The Alps
- Overboard
- overclocking
- Overcooked
- Overcooked 2
- Overcooked! All You Can Eat
- Overcrowd: A Commute ‘Em Up
- Overdungeon
- Overfall
- Overgrowth
- Overkill's The Walking Dead
- Overland
- Overload
- Overlord
- Overlord II
- Overlord: Fellowship of Evil
- Overpass
- Override: Mech City Brawl
- Overstep
- Overwatch
- Overwatch 2
- Overwhelm
- Owlboy
- Oxenfree
- Oxenfree II: Lost Signals
- Oxygen
- Oxygen Not Included