Owls are in the order Strigifromes consisting of solitary and mostly nocturnal birds of prey. The two main families in this order are Strigidae (typical owls) with 23 living genera and Tytonidae (large heart shaped faced owls) with two genera. The genera for these two families are listed below.

Family Strigidae
Aegolius: saw-whet owls, four species
Asio: eared owls, 6–7 species
Hawaiian Short-eared Owl
Asio flammeus sandwichensis
Long-eared Owl Asio otis
Athene:2–4 species burrowing owl
Burrowing Owl
Athene cunicularia
Little Owl, German Owl Athene noctua
Bubo: horned owls, eagle-owls and fish-owls, some 25 species
Great Horned Owl
Bubo virginianus
Ciccaba: four species
Glaucidium: pygmy-owls, about 30–35 species
Ferruginous Pygmy Owl Glaucidium brasilianum
Gymnoglaux: Bare-legged Owl or Cuban Screech-owl
Jubula: Maned Owl
Lophostrix: Crested Owl
Megascops: screech-owls, some 20 species
Pacific Screech Owl Megascops cooperi
Whiskered Screech Owl
Megascops trichopsis
Elf Owl Micrathene whitneyi
Mimizuku: Giant Scops-owl or Mindanao Eagle-owl
Ninox: Australasian hawk-owls, some 20 species
Morepork, Tasmanian Spotted Owl
Ninox novaeseelandiae
Nesasio - Fearful Owl
Otus: scops-owls; probably paraphyletic, about 45 species
Common Screech Owl Otus asio
Pseudoscops: Jamaican Owl and possibly Striped Owl
Ptilopsis: white-faced owls, two species
Pulsatrix: spectacled owls, three species
Pyrroglaux: Palau Owl
Strix: earless owls, about 15 species
Great Grey Owl
Strix nebulosa
Black-and-white Owl Strix nigrolineata
Surnia: Northern Hawk-owl
Uroglaux: Papuan Hawk-owl
Xenoglaux: Long-whiskered Owlet

Family Tytonidae
Barn Owl Tyto alba
Phodilus Bay owls