List of fictional extraterrestrial species and races: O


NameSourceType
OansDC ComicsAn ancient humanoid species and the founders of the Green Lantern Corps.
OannesBabylonian mythologyHumanoid
OankaliOctavia Butler's Xenogenesis series
OasianRoswell New Mexico
Ob'ennSchlock Mercenary
OcampaStar TrekHumanoid
OculonsAscendancyHumanoid
OgriDoctor Who
OgronsDoctor WhoHumanoid
Old OnesWarhammer 40,000
OliveAdventure Time: Distant LandsShape-shifting service droid
Omicronians / PopplersFuturama
OodDoctor WhoSquid-like Humanoid
OpteraDoctor Who
OrandoansDC Comics' Legion of Super-HeroesA humanoid species from the planet Orando. Legion member Princess Projectra is an Orandoan. In post-Zero Hour continuity, the Orandans are snake-like aliens, with Sensor being their representative.
OrfaAscendancy
OrganiansStar TrekEnergy beings dedicated to stopping all forms of violence.
OrgalorgAdventure TimeA malevolent primordial space deity who takes the form of the penguin Gunter. He is from an unnamed slimy planet.
OriStargate SG-1Humanoid, Ascended to a higher plain of existence in non-corporial form
OrionStar TrekGreen-skinned humanoids known for the illegal trade their extremely attractive females as slaves.
Orion RoguesBattlelords of the 23rd Century
OrionsMaster of Orion
OrishanBen 10A race of mollusk-like humanoids from the desert planet Kiusana in the Andromeda Galaxy. They can absorb and redirect moisture.
OrkansMork and Mindy
OrksWarhammer 40,000Humanoid
OrsiansTracker
OrtheansMary Gentle's Golden WitchbreedHumanoid
OrtogStar Control
OrzStar Control
OscarTommy and OscarFun and weird pink alien.
OscillatorAdventure Time: Fionna and Cake
OsiriansL. Sprague de Camp's Viagens Interplanetarias SeriesTelepathic saurians.
OutsidersLarry Niven's Known Space
OverlordsChildhood's End by Arthur C. ClarkeCreatures with the appearance of demons that help shape the evolutionary patterns of other races.
OwaStar Control 3