- Oasis Hummingbird
- Ocellated Turkey
- Olivaceous Woodcreeper
- Olive-throated Parakeet
- Olive Bee-eater
- Olive Thrush
- Olive Woodpecker
- Orange-bellied Flowerpecker
- Orange-bellied Leafbird
- Orange-billed Nightingale-Thrush
- Orange-breasted Green Pigeon
- Orange-breasted Sunbird
- Orange-chinned Parakeet
- Orange-fronted Parakeet
- Oriental Darter
- Oriental Dollarbird
- Oriental Magpie-Robin
- Oriental Pied Hornbill
- Ortolan Bunting
- Osprey
- Ovenbird