- 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
- Outer Banks
- Outer Dark
- Outer Islands
- Outer Mongolia
- Outer rim
- Outlands
- Outlier
- Outpost
- Outpost 1
- Outpost 10
- Outpost 11
- Outpost 12
- Outpost 13
- Outpost 14
- Outpost 15
- Outpost 16
- Outpost 17
- Outpost 18
- Outpost 19
- Outpost 2
- Outpost 20
- Outpost 21
- Outpost 22
- Outpost 23
- Outpost 293
- Outpost 3
- Outpost 32
- Outpost 4
- Outpost 40
- Outpost 5
- Outpost 6
- Outpost 7
- Outpost 771
- Outpost 79
- Outpost 8
- Outpost 9
- Outpost Ch'targh
- Outpost Delta 08
- Outpost Delta 1
- Outpost Delta 2
- Outpost Delta 3
- Outpost Delta 4
- Outpost Delta 5
- Outpost Delta 6
- Outpost Delta 7
- Outpost Delta 8
- Outpost Delta 9
- Outpost Epsilon 1
- Outpost Epsilon 10
- Outpost Epsilon 11
- Outpost Epsilon 2
- Outpost Epsilon 3
- Outpost Epsilon 4
- Outpost Epsilon 5
- Outpost Epsilon 6
- Outpost Epsilon 7
- Outpost Epsilon 8
- Outpost Epsilon 9
- Outpost Gi'ral
- Outpost Hadrian
- Outpost Hunter
- Outpost Kretorg
- Outpost Omega-70
- Outpost Quebec Alpha
- Outpost Seran T-1
- Outpost T-22
- Outpost Tarsus IV
- Outworlds
- Ouueqeu
- Ouzoqip
- Ova Daraan
- Ovanim
- Ovarani Valley
- Ovarian resequencing
- Ovellion
- Over a Torrent Sea
- Overfield class
- Overgeneral
- Overgrown Caves
- Overlooker
- Overminister of the Vostigye Union
- Overne
- Overne III
- Overpopulation Crisis of 17231
- Overseer
- Oversight process
- Oversoul
- Ovirapt
- Ovirian
- Ovlon
- Ovlon II
- Ovvaki's Place
- Ow'rik
- Owen Paris
- Owen Paris (mirror)
- Owen Salazar-Tucker
- Owens (Science Officer)
- Owens (Technician)
- Owon eggs
- Ox
- Oxford
- Oxford Dictionary of Terran Languages
- Oxil
- Oxinamicus
- Oxinamicus (23rd century)
- Oxira
- Oxis Dey
- Oxmyx (mirror)
- Oxoma
- Oxygen
- Oyama
- Oyama (disambiguation)
- Oyarsa Prime Shipyard
- Oydia
- Oyster
- Oyya
- Ozaba
- Ozannot
- Ozari
- Ozari-thul
- Ozcice
- Ozla Graniv
- Ozmani
- Ozone
- Ozone layer
- Ozuk
- Ozzie
- Ozzymand
- P'Jem
- P'Jem (planet)
- P'Tash
- P'alblaakis
- P'eltac cake
- P'i p'a
- P'losie
- P'losie wine
- P'rang
- P'tak
- P'tra class
- P'u tzu
- P-38
- P-38 Lightning
- P-39 Airacobra
- P-51 Mustang
- P.F. Flyers
- P.T. Barnum
- P. Carter
- P. Lauritson
- P. Matthews
- P. O'Harra
- P. Strong
- P. Walker
- P3-T3R
- P4T-16 Singularity
- P5115
- P7-Red
- P8 Blue
- PA35-15497
- PA35-15784
- PA35-16448
- PA35-16845
- PA35-18978
- PA35-34632
- PA35-38424
- PA35-38482
- PA35-46818
- PA35-48648
- PA35-48962
- PA35-54835
- PA35-54891
- PA35-58471
- PA35-71967
- PA35-73743
- PA35-74564
- PA35-76119
- PA35-79244
- PA35-84388
- PA35-84487
- PA35-86248
- PA35-86287
- PA35-94684
- PADD
- PC
- PGBC
- PIH class
- PIqaD
- PK Alpha
- POL-1
- POL-10
- POL-11
- POL-12
- POL-2
- POL-3
- POL-4
- POL-5
- POL-6
- POL-7
- POL-8
- POL-9
- PQ-1
- PSR 418-D/1015.3
- PT-009
- PWB
- PWB Aj'rmr
- PWB Koderex
- PWB Preceptor
- PWB T'Tpalok
- PWB Tomal
- PX1N4-152 Singularity
- PXK reactor
- P and L statement
- Pa'Dan's ship
- Pa'Dan family