| OGAE | OGAE Second Chance Contest | Ogam |
| OGame | Ogame | Oganesson |
| Oganessonisotoper | Ogarjova, 6 | Ogbomoso |
| OGC Nice | OGC Nice Côte d'Azur Handball | OGC Nice-Côte d'Azur |
| OGCM | OGCM'er | Ogden (Utah) |
| Ogden's Nut Gone Flake | Ogdens' Nut Gone Flake | Ogdoad |
| Ogenyi Onazi | Ogetsu-no-hime | Ogg |
| Ogg Media | Ogg Vorbis | Oggevatn Station |
| Oggi og kakerlakkerne | Ogginoggen | Oggy og kakerlakkerne |
| Oghenekaro Etebo | Oglak Tartis | OGLE-2005-BLG-390Lb |
| Ogliastra (provins) | Ogmore Castle | Ogna |
| Ogna Station | Ognenny Ostrov | Ognennye vjorsty |
| Ogni pritona | Ognjen Vukojević | Ognjen Vukojevic |
| Ogon | Ogon, voda i... mednyje truby | Ogonek |
| Ogopogo | Ograzhden (bjerg) | Ogre |
| Ogre (Letland) | Ogre (Warcraft) | Ogre, Letland |
| Ogres distrikt | Også dig, Brutus | Også dig, Brutus? |
| Også i dag | Også Viborg | Oguchi Onyewu |
| Ogulin | Ogun (delstat) | Oguta (sø) |
| Oguzhan Aynaoglu | Ogygia | Oh Happy Day |
| Oh Land | Oh Land (album) | Oh My Ghost |
| Oh My Heart | Oh No Ono | Oh No, Not You Again |
| Oh Seong-ok | Oh What a Cadillac | Oh, Boy! (film fra 1919) |
| Oh, by the Way | Oh, har du en fader! | Oh, Johnny! |
| Oh, Lady, Lady | Oh, What a Knight! | Oh, You Women! |
| OH-6A | Ohalo | Ohalo II |
| Ohře | OHCHR | OHIM |
| Ohio | Ohio County | Ohio River |
| Ohio State | Ohio State universitet | Ohio State University |
| Ohio Wesleyan University | Ohio-floden | Ohio-klassen |
| Ohiofloden | Ohios flag | OHK Dynamo |
| Ohl | OHL | Ohlstadt |
| Ohm | Ohmmeter | Ohms lov |
| Ohms Lov | Ohmsk forbindelse | Ohmsk kontakt |
| Ohmsk modstand | Ohmsk overgang | Ohmsk tab |
| Ohmske forbindelser | Ohmske kontakter | Ohmske modstande |
| Ohmske overgange | Ohmske tab | OhmyNews |
| Ohne dich | OHO | Ohre |
| Ohrid | Ohrid-Prespa grænseoverskridende biosfærereservat | Ohrid-søen |
| Ohridsøen | Ohrmazd | Ohs |
| Ohsabanan | OHSAS | Ohsbanen |
| Oi! | OIC | OIC (islam) |
| Oicho-Kabu | Oidipos | Oie |
| Oier Lazkano | Oier Olazabal | Oier Olazábal |
| Oijen (Noord-Brabant) | Oik | Oikologoi Prasinoi |
| Oikos | Oikos (tidsskrift) | OIL |
| Oil and Water | Oil Fuel Hulk C77 | Oilly Wallace |
| Oilskin | OIM | Oin |
| Oingo Boingo | Oinochoe | OIO |
| OIO-kataloget | Oireachtas | Oirschot |
| OIS | Oise | Oister |
| OiSTER | OiSTER ApS | Oisterwijk |
| Oita Trinita | Oite | Oiti |
| Oiva Lommi | Oj, svijetla majska zoro | Ojaswi Rajanya Orden |
| Ojat | Ojców Nationalpark | Ojcow Nationalpark |
| Oji Paper Company | Ojibwa | Ojmjakon |
| Ojo de Agua | Ojos del Salado | OK |
| Ok | OK a.m.b.a. | OK Benzin |
| OK Computer | Ok Computer | OK Go |
| Ok Go | OK jolle | Ok ok boys |
| OK Olie | OK Pan Aarhus | OK Vendelboerne |
| OK-Fonden | OK-jolle | OK-Klubben |
| OK-Q8 | OK-strejkerne 2008 | OK13 |
| OK2010 | Oka | Oka (Angara) |
| Oka (flod) | Oka (rodfrugt) | Okajama Slot |
| Okamiden | Okapi | Okapi Vildtreservat |
| Okapi Wildlife Reserve | Okapia | Okapia johnstoni |
| Okarina | Okavango | Okavango (flod) |
| Okavangobassinet | Okavangodeltaet | Okay |
| Okay (film) | Okay Okay Boys | Okay Tone |
| Okay tone | Okay? | Okayama |
| Okayama (præfektur) | Okayama Slot | Okayama-præfekturet |
| Oke Akpoveta | Okeanide | Okeanos |
| Okeechobee | Okehampton Castle | Oker |
| Okfjorden | OKG | OKH |
| Okh uzj eta Nastja! | Okhaldhunga District | Okhaldhunga distrikt |
| Okholm | Okholm Sogn | Okhota na lis |
| Okhota na piranju | Okhotnik | Okhotsk |
| Okhotske hav | Okhotske Hav | Okhotskhavet |
| Okhta | Okhtyrka | Okhtyrka rajon |
| OKI | Oki Electric Industry | Okinawa |
| Okinawa (ø) | Okinawa (by) | Okinawa (flertydig) |
| Okinawa (præfektur) | Okinawa ko budo | Okinawa ko-budo |
| Okinawa kobudo | Okinawa soba | Okinawa-præfekturet |
| Okinawan Kobudō | Okinawan kobudō | Okinawan kobudo |
| Okinawarikse | Okipa-ceremonien | Okitsune-sama de Chu |
| Okjeo | Okker | Okker gokker |
| Okkerbrystet biæder | Okkergul pletvinge | Okkergul randøje |
| Okkerhalet seglnæbskolibri | Okkerhalet Seglnæbskolibri | Okkertræand |
| Okkervil River | Okklusion | Okklusionstræning |
| Okkult | Okkultation | Okkultisme |
| Okkultismen | Okkultist | Okkupation |
| Okkupere | Oklahoma | Oklahoma City |
| Oklahoma City (Oklahoma) | Oklahoma City Thunder | Oklahoma City, Oklahoma |
| Oklahoma City-bombningen | Oklahoma RedHawks | Oklahomas flag |
| Oklokrati | Oklungen Station | Okmulgee |
| Okno v Parizj | OKO | Okolner |
| Okolo Slovenska | Okome sogn | Okonomiyaki |
| Okotoks vandreblokken | Okotoks-vandreblokken | OKQ8 |
| Okra | Okraina | Okraina (film fra 1933) |
