| Obus elizabethae | Obus infirmus | Obuz, Elâzığ |
| Obuz, Tatvan | Obuzbaşı, Mazgirt | Obvious (bài hát của Westlife) |
| Obwalden | Obwalden (bang) | Obyčtov |
| Obyekt 195 | Obyekt 279 | Obytce |
| Obzor | OC-14 | OC-14 Groza |
| OC-14-4A | OC-ute | Oca |
| Ocaña | Ocaña, Tây Ban Nha | Ocadia glyphistoma |
| Ocak, Aziziye | Ocak, Kemaliye | Ocak, Pazar |
| Ocak, Yomra | Ocakbaşı, Üzümlü | Ocakbaşı, Delice |
| Ocakbaşı, Erbaa | Ocakbaşı, Tutak | Ocaklar, Erdek |
| Ocaklı, Aşkale | Ocaklı, İdil | Ocaklı, Ödemiş |
| Ocaklı, Dinar | Ocaklı, Gelibolu | Ocaklı, Kars |
| Ocaklı, Maçka | Ocaklı, Mustafakemalpaşa | Ocaklı, Nazilli |
| Ocaklı, Pazar | Ocaklı, Sorgun | Ocaklı, Tuşba |
| Ocaklı, Van | Ocaklı, Varto | Ocaktaşı, Şebinkarahisar |
| Ocala, Florida | Ocalaria | Ocalaria cohabita |
| Ocalaria dioptica | Ocalaria guarana | Ocalaria macrops |
| Ocalaria oculata | Ocalaria pavina | Ocalaria pavo |
| Ocalaria quadriocellata | Ocalea (chi bọ cánh cứng) | Ocalemia borneensis |
| Ocalemia carpo | Ocalemia hayashii | Ocalemia vigilans |
| OCaml | Ocamonte | Ocampo, Chihuahua |
| Ocampo, Coahuila | Ocampo, Durango | Ocampo, Guanajuato |
| Ocampo, Michoacán | Ocampo, Tamaulipas | Ocana, Corse-du-Sud |
| Ocara | Ocaria | Ocarina |
| Ocauçu | Ocón | Ocú (huyện) |
| OCB | Ocb | OCB Bank |
| OCB Vietnam | Occagnes | Occapes distinctor |
| Occapes hinzi | Occapes sierrae | Occey |
| Occhiatana | Occhieppo Inferiore | Occhieppo Superiore |
| Occhiobello | Occia ashmeadi | Occia elegans |
| Occia pulchella | Occidental Mindoro | Occidental Mindoro (tỉnh) |
| Occidentalia | Occidentalia comptulatalis | Occidentophosis damarina |
| Occidozyga | Occidozyga baluensis | Occidozyga borealis |
| Occidozyga celebensis | Occidozyga diminutivus | Occidozyga floresiana |
| Occidozyga floresianus | Occidozyga laevis | Occidozyga lima |
| Occidozyga magnapustulosus | Occidozyga semipalmata | Occidozyga semipalmatus |
| Occidozyga sumatrana | Occidozyga vittatus | Occimiano |
| Occisor atratus | Occisor inscitus | Occisor versutus |
| Occitanie | Occitanosaurus | Occoches |
| Occupy Central | Occupy Wall Street | OCD |
| OCEAN | Ocean City, New Jersey | Ocean Eyes |
| Ocean Girl | Ocean Odyssey | Ocean Springs, Mississippi |
| Ocean Waves | Ocean's 8 | Ocean's Eleven (phim năm 2001) |
| Oceania Football Confederation | Oceanites | Oceanites gracilis |
| Oceanites gracilis galapagoensis | Oceanites gracilis gracilis | Oceanites oceanicus |
| Oceanites oceanicus exasperatus | Oceanites oceanicus oceanicus | Oceanodroma |
| Oceanodroma castro | Oceanodroma furcata | Oceanodroma furcata furcata |
| Oceanodroma furcata plumbea | Oceanodroma homochroa | Oceanodroma hornbyi |
| Oceanodroma jabejabe | Oceanodroma leucorhoa | Oceanodroma macrodactyla |
| Oceanodroma markhami | Oceanodroma matsudairae | Oceanodroma melania |
| Oceanodroma microsoma | Oceanodroma monorhis | Oceanodroma monteiroi |
| Oceanodroma tethys | Oceanodroma tethys kelsalli | Oceanodroma tethys tethys |
| Oceanodroma tristrami | Oceanopapaver | Oceanside, California |
| Ocella | Ocellochloa | Ocellochloa rudis |
| Ocenebra | Ocenebra acanthophora | Ocenebra brevirobusta |
| Ocenebra chavesi | Ocenebra erinacea | Ocenebra inornata |
| Ocenebra lumaria | Ocenebrinae | Ocenotrophon |
| Ocenotrophon painei | Ocentejo | Ochagavía |
| Ochagavia | Ochagavia andina | Ochagavia carnea |
| Ochagavia elegans | Ochagavia litoralis | Ochakiv |
| Ochakiv (huyện) | Ochancourt | Ochanostachys |
| Ochanostachys amentacea | Ochánduri | Ochersky (huyện) |
| Oches | Ochetarcha | Ochetodillo sulcatus |
| Ochetophila nana | Ochetophila trinervis | Ochetorhynchus |
| Ochetorhynchus andaecola | Ochetorhynchus melanurus | Ochetorhynchus melanurus atacamae |
| Ochetorhynchus melanurus melanurus | Ochetorhynchus phoenicurus | Ochetorhynchus ruficaudus |
| Ochetorhynchus ruficaudus famatinae | Ochetorhynchus ruficaudus montana | Ochetorhynchus ruficaudus ruficaudus |
| Ochey | Ocheyedan, Iowa | Ocheyedan, Quận Osceola, Iowa |
| Ochiai Hiroshi | Ochicanthon | Ochicanthon besucheti |
| Ochicanthon cambeforti | Ochicanthon ceylonicus | Ochicanthon cingalensis |
| Ochicanthon crockermontis | Ochicanthon crypticus | Ochicanthon danum |
| Ochicanthon deplanatus | Ochicanthon devagiriensis | Ochicanthon dulitmontis |
| Ochicanthon dytiscoides | Ochicanthon edmondsi | Ochicanthon ernei |
| Ochicanthon gangkui | Ochicanthon gauricola | Ochicanthon hanskii |
| Ochicanthon hikidai | Ochicanthon javanus | Ochicanthon karasuyamai |
| Ochicanthon kikutai | Ochicanthon kimanis | Ochicanthon laetus |
| Ochicanthon loebli | Ochicanthon maryatiae | Ochicanthon masumotoi |
| Ochicanthon mulu | Ochicanthon murthyi | Ochicanthon mussardi |
| Ochicanthon neglectus | Ochicanthon nitidus | Ochicanthon obscurus |
| Ochicanthon ochii | Ochicanthon oharai | Ochicanthon peninsularis |
| Ochicanthon punctatus | Ochicanthon rombauti | Ochicanthon takakui |
| Ochicanthon tambunan | Ochicanthon thai | Ochicanthon thailandicum |
| Ochicanthon tristis | Ochicanthon tristoides | Ochicanthon uedai |
| Ochicanthon vazdemelloi | Ochicanthon woroae | Ochimus laetipennis |
| Ochina | Ochina latrellii | Ochina ptinoides |
| Ochiobryum | Ochiobryum blandum | Ochiobryum handelii |
| Ochlandra | Ochlandra beddomei | Ochlandra ebracteata |
| Ochlandra keralensis | Ochlandra scriptoria | Ochlandra setigera |
| Ochlandra sivagiriana | Ochlandra soderstromiana | Ochlandra spirostylis |
| Ochlandra stridula | Ochlandra talbotii | Ochlandra travancorica |
| Ochlandra wightii | Ochlenberg | Ochlerotatus |
| Ochlerotatus serratus | Ochlerotatus sticticus | Ochlerotatus stimulans |
| Ochlerotatus triseriatus | Ochlia | Ochlogramma cumingii |
| Ochna | Ochna andravinensis | Ochna angustata |
| Ochna arenaria | Ochna barteri | Ochna beirensis |
| Ochna bernieri | Ochna boiviniana | Ochna ciliata |
| Ochna cinnabarina | Ochna elegans | Ochna gambleoides |
| Ochna gamostigmata | Ochna hiernii | Ochna holstii |
| Ochna humblotiana | Ochna integerrima | Ochna katangensis |
| Ochna latisepala | Ochna leptoclada | Ochna madagascariensis |
