| Black-collared Apalis Oreolais pulcher | Passeriformes / Cisticolidae | LC |
| Rwenzori Apalis Oreolais ruwenzorii | Passeriformes / Cisticolidae | LC |
| Akikiki Oreomystis bairdi | Passeriformes / Fringillidae | CR |
| Bearded Mountaineer Oreonympha nobilis | Apodiformes / Trochilidae | NE |
| Horned Guan Oreophasis derbianus | Galliformes / Cracidae | EN |
| Roberts's Warbler Oreophilais robertsi | Passeriformes / Cisticolidae | LC |
| Tawny-throated Dotterel Oreopholus ruficollis | Charadriiformes / Charadriidae | LC |
| Bolivian Blackbird Oreopsar bolivianus | Passeriformes / Icteridae | LC |
| Plum-faced Lorikeet Oreopsittacus arfaki | Psittaciformes / Psittaculidae | LC |
| Mountain Quail Oreortyx pictus | Galliformes / Odontophoridae | LC |
| Sage Thrasher Oreoscoptes montanus | Passeriformes / Mimidae | LC |
| Fernwren Oreoscopus gutturalis | Passeriformes / Acanthizidae | EN |
| Mountain Firetail Oreostruthus fuliginosus | Passeriformes / Estrildidae | LC |
| Flame-throated Warbler Oreothlypis gutturalis | Passeriformes / Parulidae | LC |
| Crescent-chested Warbler Oreothlypis superciliosa | Passeriformes / Parulidae | LC |
| Tanager Finch Oreothraupis arremonops | Passeriformes / Passerellidae | LC |
| Wedge-tailed Hillstar Oreotrochilus adela | Apodiformes / Trochilidae | LC |
| Ecuadorian Hillstar Oreotrochilus chimborazo | Apodiformes / Trochilidae | LC |
| Blue-throated Hillstar Oreotrochilus cyanolaemus | Apodiformes / Trochilidae | CR |
| Andean Hillstar Oreotrochilus estella | Apodiformes / Trochilidae | LC |
| White-sided Hillstar Oreotrochilus leucopleurus | Apodiformes / Trochilidae | LC |
| Black-breasted Hillstar Oreotrochilus melanogaster | Apodiformes / Trochilidae | LC |
| Green-headed Hillstar Oreotrochilus stolzmanni | Apodiformes / Trochilidae | LC |
| Rusty Mouse-warbler Origma murina | Passeriformes / Acanthizidae | LC |
| Mountain Mouse-warbler Origma robusta | Passeriformes / Acanthizidae | LC |
| Rockwarbler Origma solitaria | Passeriformes / Acanthizidae | LC |
| Bernier's Vanga Oriolia bernieri | Passeriformes / Vangidae | EN |
| White-lored Oriole Oriolus albiloris | Passeriformes / Oriolidae | LC |
| African Golden Oriole Oriolus auratus | Passeriformes / Oriolidae | LC |
| Black-eared Oriole Oriolus bouroensis | Passeriformes / Oriolidae | LC |
| Western Oriole Oriolus brachyrynchus | Passeriformes / Oriolidae | LC |
| Green-headed Oriole Oriolus chlorocephalus | Passeriformes / Oriolidae | LC |
| Black-and-crimson Oriole Oriolus consanguineus | Passeriformes / Oriolidae | LC |
| Ventriloquial Oriole Oriolus consobrinus | Passeriformes / Oriolidae | LC |
| Sao Tome Oriole Oriolus crassirostris | Passeriformes / Oriolidae | VU |
| Javan Oriole Oriolus cruentus | Passeriformes / Oriolidae | DD |
| Tanimbar Oriole Oriolus decipiens | Passeriformes / Oriolidae | LC |
| Wetar Oriole Oriolus finschi | Passeriformes / Oriolidae | LC |
| Green Oriole Oriolus flavocinctus | Passeriformes / Oriolidae | LC |
| Grey-collared Oriole Oriolus forsteni | Passeriformes / Oriolidae | LC |
| Black Oriole Oriolus hosii | Passeriformes / Oriolidae | NT |
| Isabela Oriole Oriolus isabellae | Passeriformes / Oriolidae | CR |
| Black-headed Oriole Oriolus larvatus | Passeriformes / Oriolidae | LC |
| Timor Oriole Oriolus melanotis | Passeriformes / Oriolidae | LC |
| Ethiopian Oriole Oriolus monacha | Passeriformes / Oriolidae | LC |
| Black-winged Oriole Oriolus nigripennis | Passeriformes / Oriolidae | LC |
| Mountain Oriole Oriolus percivali | Passeriformes / Oriolidae | LC |
| Dusky-brown Oriole Oriolus phaeochromus | Passeriformes / Oriolidae | LC |
| Olive-backed Oriole Oriolus sagittatus | Passeriformes / Oriolidae | LC |
| Philippine Oriole Oriolus steerii | Passeriformes / Oriolidae | LC |