- Order of the Bat'leth
- Order of the Faceless
- Order of the Faithful
- Order of the Gods
- Order of the Guardians
- Order of the Shield of Medusa
- Order of the Temple
- Ordinary Days
- Ordover
- Ordover (USS Enterprise)
- Ordover (USS Enterprise-D)
- Ordover (animal)
- Ordover system
- Ordoñez
- Ordro
- Ore
- Ore (animal)
- Ore (disambiguation)
- Ore cannon
- Ore processing center
- Orean Ocean
- Oregon
- Orelious IX
- Orelix
- Orellius
- Orellius sector block
- Orelte
- Orendal
- Orenthal Hawkins
- Oreopolis
- Oresis
- Orestes
- Orezes Codices
- Orfil Quinteros
- Orfil Solis
- Organ of Zuckerkandl
- Organa
- Organia
- Organia (mirror)
- Organia system
- Organian
- Organian (mirror)
- Organian Council of Elders
- Organian Peace Treaty
- Organic farming
- Organized crime
- Orgill
- Orgon
- Orgone
- Oriana (planet)
- Oriana D'Amato
- Orias
- Orias III
- Orias sector
- Oridex
- Oriens Delta
- Oriens Gamma III-B
- Orient
- Orientis Gamma III-B
- Origin of Data
- Original Sin
- Originators
- Origins
- Origins and Examples of the Ferengi Rules of Acquisition
- Orihar'du
- Orilly Malar
- Orinoco River
- Orion
- Orion's Hounds
- Orion (disambiguation)
- Orion (halfbreed)
- Orion (mirror)
- Orion (reptilian)
- Orion (ship)
- Orion (slang)
- Orion (space station)
- Orion Alliance
- Orion Arm
- Orion Arm (disambiguation)
- Orion Arm (region)
- Orion Association
- Orion Cabal
- Orion Codebreaker
- Orion Colonies
- Orion Colonies Intelligence
- Orion Commercial States
- Orion Complex
- Orion Congeries
- Orion Dawn
- Orion Depository
- Orion Emigration Act
- Orion Empire
- Orion Era
- Orion Free States
- Orion Free Traders
- Orion Freedom League
- Orion Frontier Mercantile Association
- Orion I
- Orion II
- Orion Indian Summer
- Orion Institute of Cosmology
- Orion Marketing
- Orion Nebula
- Orion Neutrality Act
- Orion Neutrality Area
- Orion Prime
- Orion Provincial Senate
- Orion Registry
- Orion Rising
- Orion Ruse
- Orion Space Navy
- Orion Syndicate
- Orion Syndicate (mirror)
- Orion Syndicate Economic Protocols
- Orion Union
- Orion Victory League
- Orion War
- Orion ale
- Orion beer
- Orion blood fever
- Orion captain
- Orion chancellor
- Orion class
- Orion constellation
- Orion corvette
- Orion dreadnought
- Orion emerald finch
- Orion energy orb
- Orion fern tree
- Orion firepot
- Orion freebooter ship
- Orion history
- Orion interceptor
- Orion language
- Orion outpost
- Orion pirate ship
- Orion plague
- Orion raider
- Orion rum
- Orion salvage cruiser
- Orion scout ship
- Orion sector
- Orion slave girl
- Orion slaver
- Orion slavery
- Orion spices
- Orion starships
- Orion tapestry
- Orion tea
- Orion whiskey
- Orion wine
- Orisha
- Orishan
- Orishan language
- Orisi
- Orisin Dever
- Orith II
- Orithian creeper
- Oritixx
- Orix
- Orjax Cluster
- Orkett's disease
- Orlando
- Orlando Post Dispatch
- Orleans Parish Hospital
- Orlenti
- Orlian Quadrant
- Orloc
- Orm Trelar
- Ormachi
- Ormoch
- Ormuk
- Orna
- Ornak
- Ornara
- Ornathia Delle
- Ornathia Harta
- Ornathia Lac
- Ornathia Nerissa
- Ornathia Sten
- Ornathia Taryl
- Ornathia class
- Ornathia resistance cell
- Ornithar
- Ornsdorf
- Oroborus virus
- Orojop
- Oromente Qualfn
- Oroness
- Ororo Munroe
- Orosz
- Orpax
- Orphans
- Orphans (comic)
- Orphans (eBook)
- Orphans (short story)
- Orpheus
- Orpheus (freighter)
- Orpheus (space station)
- Orpheus Mining Colony
- Orr ni'Li
- Orren Ran
- Orrible Cannon
- Orrix
- Orruk
- Orsa
- Orsak
- Orser
- Orshan
- Orson Welles
- Orta
- Ortadd galaxy
- Ortak Badlands
- Ortees Sharad
- Ortega
- Ortella
- Ortexa
- Orthak
- Orthew
- Orthodox Andorian Vengeance Cycle
- Orthoo
- Orthoo (planet)
- Ortikan
- Ortikant
- Ortiz
- Ortiz (Lieutenant)
- Orvat
- Orventa T'Jul
- Orventis Arena
- Orveth
- Orville Wright
- Orvor
- Orwell
- Orwell IV
- Orynchid
- Oryza egregia
- Osadj
- Osadjani
- Osaka (disambiguation)
- Osaka class
- Osborne
- Osborne's World
- Osborne (disambiguation)
- Osborne Hardison
- Oscar (disambiguation)
- Oscar Diamond
- Oscar Kravickowski
- Oscar Wilde
- Oscar Wilde (mirror)
- Oschu class
- Oscoid
- Osdol Bria
- Osena
- Osgood
- Oshima
- Oshionian
- Osik
- Osinar
- Osinar VI
- Osiris
- Osiris (disambiguation)
- Osiris VII
- Osiris system
- Oskaloosa
- Oskaloosa log
- Oskria
- Oslan silk
- Oslo
- Oslo (disambiguation)
- Oslo class
- Osmium
- Osmotic eel
- Osol twist
- Osric Whipple
- Ossec
- Osseo Bemidji
- Ossium
- Ostellon
- Ostenex-D
- Ostenex-E
- Osteofuser
- Osteoporosis
- Osteoregenerator
- Ostratus
- Ostrich
- Oswald (mirror)
- Oswaldites
- Oswind
- Osyraa
- Otamad
- Otamawan
- Otan
- Otana
- Otanda
- Otari II
- Otari II outpost
- Otarian
- Otera Tul
- Otevrel
- Otha (planet)
- Otha Prime
- Othan sector
- Othello
- Othello (planet)
- Othello (play)
- Othello 1
- Othello Beck
- Othello Beck's wife
- Other-worlder
- Other Realities
- Other short stories
- Otora
- Otram
- Otroya
- Otroya II
- Ottawa
- Ottawa (USS Titan)
- Otter
- Otter (disambiguation)
- Otto
- Otto von Bismarck
- Otton
- Otwa Tandewan
- Oubliette
- Oueum
- Ouija board
- Ouoee
- Oupia
- Our Chance for Peace
- Our Dearest Blood
- Our Lady of Significant Mercy Hospital
- Our Man Bashir
- Our Million-Year Mission
- Our man
- Ourentia
- Ouroboros
- Ouroboros class
- Ousmanova
- Out There
- Out in the Cold
- Out of Time
- Out of the Box, Thinking
- Out of the Cocoon
- Out of the Cocoon (omnibus)
- Out of the Frying Pan