Старонкі з назвамі на ўзор
- O.Torvald
- O2 Арэна (Лондан)
- O2 Арэна (Прага)
- OB-асацыяцыя Скарпіёна — Цэнтаўра
- OF-40
- OFB MPV
- OMV
- OMX Group
- OMX Nordic 40
- OMX Stockholm 30
- ONUKA
- OS/2
- OXO
- O (літара)
- O tempora, o mores!
- Oasis
- Obie
- Objective-C
- Obsidian Entertainment
- Ochodaeus chrysomeloides
- Ochropacha duplaris
- Ochsenheimeria taurella
- Ochsenheimeria vacculella
- Odiellus spinosus
- Odontobutidae
- Oecetis
- Oecophoridae
- Oedemopsis
- Oenanthe crocata
- Oesophagostomum cervi
- Oesophagostomum columbianum
- Oesophagostomum dentatum
- Oesophagostomum longicaudum
- Oestroidea
- Official Xbox Magazine
- Ogcodes
- Oklahoma
- Okular
- Oleg Jagger
- Olethreutes arcuella
- Oligolophus tridens
- Oligostomis
- Oligotricha
- Omar Rodriguez Lopez Quintet
- OmegaT
- Omphalodes cappadocica
- Omut
- On an Island
- Onchocerca cervicalis
- Onchocerca flexuosa
- Onchocerca gutturosa
- Oncocera semirubella
- Oncorhynchus tshawytscha
- OnePlus 2
- OnePlus One
- OneRepublic
- One Canada Square
- One Direction
- One More Time (сінгл)
- One Voice (альбом)
- One Voice (сінгл)
- Onegin
- Oniscidae
- Onliner.by
- Only Teardrops
- Onnia
- Onychocola canadensis
- Oocatochus rufodorsatus
- Oodji
- Oophaga pumilio
- Oops
- Opel
- Opel Insignia
- Opel Kadett
- Opel Omega
- Opel Zafira
- OpenBSD
- OpenOffice.org
- OpenSolaris
- OpenStreetMap
- Open Database License
- Open Space
- Opera
- Opeth
- Ophidiasteridae
- Ophiocordycipitaceae
- Ophiomyia
- Ophrys apifera
- Ophrys bombyliflora
- Ophrys exaltata
- Ophrys holosericea
- Ophrys lutea
- Ophrys reinholdii
- Ophrys scolopax
- Ophrys speculum
- Ophrys sphegodes
- Ophrys tenthredinifera
- Opilio parietinus
- Opisthokonta
- Oplopanax elatus
- Opportunity (марсаход)
- Opus Anglicanum
- Opus Dei
- Opus interrasile
- Oracle
- Oracle Database
- Oracular Spectacular
- Orange Moldova
- Orchideae
- Orchidinae
- Orchidoideae
- Orchis anthropophora
- Ordem e Progresso
- Ordnance QF 25-pounder
- Oreasteridae
- Orectolobiformes
- Oregoniidae
- Organic Maps
- Orgyia antiqua
- Oriflame
- Orka
- Ornithogalum arabicum
- Ornithogalum narbonense
- Orrorin
- Orthosia gothica
- Orthotaenia undulana
- Orthriophis taeniurus
- Oryx (сайт)
- Oryzaephilus
- Oryzeae
- Oshkosh L-ATV
- Oshkosh M-ATV
- Osimira
- Ossian Studios
- Osteoglossum bicirrhosum
- Osteospermum
- Ostriv
- Otto Dix
- Our Song (песня Тэйлар Свіфт)
- Ours (песня Тэйлар Свіфт)
- Oxxxymiron