- Obama facility
- Oban (comic)
- Oban (disambiguation)
- Obanak Keelen
- Obar
- Obarakeh
- Obatta Cluster
- Obbia
- Obbia (disambiguation)
- Obble plum
- Obduli
- Obdurium
- Obe
- Obelisk
- Obelisk (disambiguation)
- Obelisk 1
- Obelisk class
- Obelisk of Luxor
- Oben
- Obena
- Obena class
- Oberon
- Oberon (disambiguation)
- Oberon class
- Oberst
- Oberth class
- Obisek
- Obitztor
- Objective: Bajor
- Objective Witness
- Objectivist-Libertarianism
- Oblat
- Oblata
- Oblatis
- Oblette
- Obligations Discharged
- Oblik
- Oblissa
- Oblivion
- Oblivion's Gate (novel)
- Oblivion (city)
- Oblivion (novel)
- Oblix
- Obora
- Obra Daraan
- Obrom
- Obrom System Patrol
- Observation lounge
- Observer Effect
- Obsession
- Obsidian
- Obsidian (disambiguation)
- Obsidian (planet)
- Obsidian Abyss
- Obsidian Alliances
- Obsidian Order
- Obsidian Order (mirror)
- Obsidian native
- Obsitrate
- Oby
- Oby VI
- Ocala Sindari class
- Ocampa
- Ocampa (star)
- Ocampa V
- Ocampa city
- Occam's Razor
- Occino
- Occipital node
- Occita's theorem
- Occult
- Occultus Ora
- Occupation of Bajor
- Ocean
- Ocean Grave
- Ocean cocoa
- Ocean of Dust
- Ocean of Storms
- Oceania
- Oceanleaf tea
- Oceanview
- Ochoa
- Ochs
- Ockmenic
- Ockmenic IX
- Ocman Danriv
- Octans
- Octanti
- Octavianius
- Octavio Hernandez
- Octavius
- Octavius IV
- Octif
- Octif I
- Octoan
- October
- Octyne
- Octyne III
- Ocular implant
- Odal
- Odallu
- Odan
- Odan (mirror)
- Ode to the Prophets
- Oden Jek
- Odib
- Odib (disambiguation)
- Odib (planet)
- Odib High Congress
- Odib system
- Odin class
- Odina-Keh
- Odira
- Odise
- Odo
- Odo's bucket
- Odo (alternates)
- Odo (cat)
- Odo (mirror)
- Odona
- Odra maVolan
- Odronix swamp extract
- Odyssean Pass
- Odysseus
- Odysseus class
- Odyssey
- Odyssey's End
- Odyssey's End (comic)
- Odyssey (disambiguation)
- Odyssey (free starship)
- Odyssey (omnibus)
- Odyssey class
- Oe'hfi'loos
- Oe'xori'kain
- Oehrima'loos
- Oenaskas
- Oerenoqha
- Oerinodro
- Oerla'qhu
- Oetalgolor
- Oetonikain
- Oexukain
- Oezor'qhu
- Of Bajor
- Of Cabbages and Kings
- Of Chaos and Kal-toh, Part 1
- Of Chaos and Kal-toh, Part 2
- Of Signs and Portents
- Of Two Minds
- Of Woman Born
- Ofelia Mavroidis
- Off the Beaten Path
- Office of Cultural Analysis
- Office of Fugitive Affairs
- Office of Historical Studies
- Office of Homeland Peace
- Office of Imperial Inquisition
- Office of Internal Security
- Officer
- Officer Exchange Program
- Officer in tactical command
- Officer of the watch
- Officers' club
- Official Biography of James T. Kirk
- Official History of Starfleet Academy
- Official Record
- Official Secrets Act
- Official Star Trek Cooking Manual
- Official Tournament Sealed Pack
- Ofish
- Ofora
- Ogar
- Ogat
- Ogat (disambiguation)
- Ogat (mirror)
- Ogat (planet)
- Ogat Station
- Ogat a
- Ogger
- Oghen (planet)
- Ogilvy
- Ogla Koke
- Oglamar-Surkan
- Ogliila eggs
- Oguran
- Ogus
- Ogus II
- Ogyas III
- Oh
- Ohalavaru
- Ohalu
- Ohalu Prophecies
- Ohio
- Ohio (disambiguation)
- Ohm
- Ohniaka
- Ohniaka III
- Ohop
- Oida age
- Oikeniwa
- Oil
- Oil and Water
- Oil heater
- Ojav
- Ojibwa
- Ojibwe
- Ok'cet
- Okado
- Okafor
- Okalan
- Okana Desert
- Okana Shipyards
- Okapu VII
- Okara spaceport
- Okeanos
- Oken'alak
- Okenga
- Okerna
- Oki Gwamningdo
- Okin Dex
- Okinawa
- Okinawa (disambiguation)
- Okinawa class
- Okira
- Oklahoma
- Okona's species
- Okor'teth
- Okrand
- Oktesh
- Okuda (disambiguation)
- Okundek Medical Facility
- Ol Daraan
- Ola class
- Olaen class
- Olaf Sondergaard
- Olahm
- Olahm Consort
- Olajawaks
- Olaras Prime
- Olaria
- Olassa
- Olaz R'Lash
- Old Bajoran
- Old Bajoran Republic
- Old Bandi City
- Old Calendar
- Old Culture
- Old Debts
- Old Doc's planet
- Old Friends, New Planets
- Old Georgetown
- Old Hebitian
- Old Hemcree
- Old High Bajoran
- Old High Martian
- Old High Rihannsu
- Old High Vulcan
- Old House Yehenik
- Old Illyan
- Old Loyalties
- Old One alpha
- Old Ones
- Old Ones (Exo III)
- Old Ones (mirror)
- Old Ones (ornithoid)
- Old Quarter
- Old Royal Naval College
- Old Soldiers Never Die
- Old Souls
- Old Tricks
- Old Wounds
- Old Wounds (comic)
- Old Wounds (novel)
- Oldan
- Oldvon
- Ole Smith
- Oleph
- Olett
- Olexan
- Olfacan
- Olga Litowinski
- Olga Ousmanova
- Oliana Mirren
- Oliara bird
- Olifir
- Olio
- Olisu
- Olive
- Olive branch
- Oliver
- Oliver (Ensign)
- Oliver Cromwell
- Oliver Rallie
- Olivia Akomo
- Olivia Bolaji
- Olivia Dellasant
- Olivia Picard
- Olivia Rose
- Olivia Woods
- Olivia de Havilland
- Olix
- Olmerak
- Olmerak Prime
- Oloara Rintel
- Ologomwi
- Olorva
- Oloss
- Olossa
- Olson
- Olson (disambiguation)
- Olson (planet)
- Oltion
- Oltion IV
- Oltonion
- Olus
- Oluvas Del
- Olvar Tarrelsen
- Olvek
- Olwyn Kadohata
- Olympia (cargo carrier)
- Olympia (disambiguation)
- Olympic Games
- Olympic class
- Olympus
- Olympus (CM-4)
- Olympus Mons
- Olympus Mons (ship)
- Omag
- Omaha
- Omani
- Omar (disambiguation)
- Omar Cadly
- Omar Station
- Omar System Patrol
- Omari-Ekon
- Omarion Nebula
- Ombrey
- Omearan
- Omearan Starsearcher
- Omega
- Omega-2 Cygni
- Omega (star)
- Omega Altair IV
- Omega Aurigae
- Omega Centus