O
- Obligations, Mutual
- Obsidian
- Obstetrics
- Ocean navigation
- Ocean-going canoes
- Ōhākī
- Ohaoha
- Ōi
- Oioi
- Old man's beard lichens
- Old Testament
- Omens, Bad
- Omens, Good
- Onetū
- Ora
- Oranges, Māori
- Orators
- Oratory
- Orchids, Bamboo
- Orchids, Easter
- Ore-rākau a tū
- Orion's Belt
- Oriori
- Ororeo
- Ororuarangi
- Otaota
- Otaota (Kai)
- Otaota hāwere
- Otaota waimāori
- Outer space
- Outrigger canoes
- Owls
- Owls, Laughing
- Oystercatchers, Black
- Oystercatchers, Pied
- Oysters
