Eight subspecies of Ninox boobook are recognised in version 10.1 of the IOC World Bird List, published in January 2020:
N. b. boobook, the nominate subspecies, is found on the Australian mainland, from southern Queensland, through New South Wales and Victoria into South Australia.
Port Augusta marks its westernmost range limit, with subspecies N. b. ocellata found westwards.
The border between these two taxa is unclear.

N. b. cinnamomina is found on Tepa and Babar Islands in the eastern Lesser Sunda Islands.
It has cinnamon upperparts, brownish crown and cinnamon-streaked underparts.
Its redder coloration and small size led German naturalist Ernst Hartert to describe it as a distinct taxon in 1906.
The call is similar to those of the Australian subspecies.

N. b. halmaturina is found on Kangaroo Island.
It was described by Australian amateur ornithologist Gregory Mathews in 1912 on the basis of darker and more reddish plumage than other subspecies.
It is sometimes included in the nominate subspecies.
It has dark brown underparts with reddish-brown rather than white markings.
Some individuals of subspecies boobook from the mainland do have similar coloration, but are consistently larger.

N. b. lurida, also known as the red boobook, is a distinctive subspecies from north Queensland.
English naturalist Charles Walter De Vis discovered it in 1887, describing it from two specimens collected in the vicinity of Cardwell.
Analysis of its DNA and call differ little from other Australian mainland subspecies.
It is small and dark compared to other subspecies, with a reddish tinge and few spots on its upperparts, and many spots on its underparts.
It also has much thinner and less obvious white eyebrows than other subspecies.

N. b. moae  is found on Moa, Leti and Romang Islands in the Lesser Sunda Islands.
It is darker than subspecies boobook.
It was described by Mayr in 1943 from a specimen collected by one H. Kühn in 1902 on Moa.
Mayr noted that it had dark reddish upperparts with pronounced barring on wings and tail, larger white spots on scapulars and buff streaks on the nape.
The call is similar to those of the Australian subspecies.

N. b. ocellata is found across northern Australia, Western Australia and western South Australia, as well as Savu near Timor.
It was described as Athene ocellata by  French biologist Charles Lucien Bonaparte in 1850, from a specimen from Raffles Bay on the Cobourg Peninsula.
It is generally lighter-coloured than other mainland boobooks, though occasional dark-plumaged individuals are seen.
The face in particular is pale, with feathers of the forehead and lores white with black shafts.
Birds from Melville Island are small and generally dark, and were previously classified as a separate subspecies melvillensis by Mathews in 1912.
Birds from southwestern Australia north to Tantabiddy on the North West Cape and Glenflorrie on the Ashburton River are relatively dark with more uniform rufous-brown underparts.
Mees classified them as a separate subspecies rufigaster.
Mayr classified the lightest birds of northern Australia as arida, medium-toned birds as mixta and darker ones macgillivrayi.
All these taxa are now regarded as ocellata.
Its call is similar to that of the nominate subspecies.

N. b. pusilla is from the southern lowlands of New Guinea, along the Oriomo and Wassi Kusa Rivers, west of the Fly River.
Described by Mayr and Canadian zoologist Austin L. Rand in 1935 from a specimen collected in Dogwa, it resembles subspecies ocellata but is smaller.

N. b. remigialis is found on the Kai Islands in the Lesser Sunda Islands.
Stresemann described it in 1930 from a specimen collected in 1909.
Poorly known, it has been recorded twice more in 1998 and 2010.
It has a call more similar to the barking owl, and might be classified as a subspecies of it instead.

Three former subspecies of Ninox boobook have been classified as distinct species since 2017: namely, Rote boobook (Ninox rotiensis), Timor boobook (N. fusca), and Alor boobook (N. plesseni).
Eight subspecies of Ninox boobook are recognised in version 10.1 of the IOC World Bird List, published in January 2020:
N. b. boobook, the nominate subspecies, is found on the Australian mainland, from southern Queensland, through New South Wales and Victoria into South Australia. Port Augusta marks its westernmost range limit, with subspecies N. b. ocellata found westwards. The border between these two taxa is unclear.
N. b. cinnamomina is found on Tepa and Babar Islands in the eastern Lesser Sunda Islands. It has cinnamon upperparts, brownish crown and cinnamon-streaked underparts. Its redder coloration and small size led German naturalist Ernst Hartert to describe it as a distinct taxon in 1906. The call is similar to those of the Australian subspecies.
N. b. halmaturina is found on Kangaroo Island. It was described by Australian amateur ornithologist Gregory Mathews in 1912 on the basis of darker and more reddish plumage than other subspecies. It is sometimes included in the nominate subspecies. It has dark brown underparts with reddish-brown rather than white markings. Some individuals of subspecies boobook from the mainland do have similar coloration, but are consistently larger.
N. b. lurida, also known as the red boobook, is a distinctive subspecies from north Queensland. English naturalist Charles Walter De Vis discovered it in 1887, describing it from two specimens collected in the vicinity of Cardwell. Analysis of its DNA and call differ little from other Australian mainland subspecies. It is small and dark compared to other subspecies, with a reddish tinge and few spots on its upperparts, and many spots on its underparts. It also has much thinner and less obvious white eyebrows than other subspecies.
N. b. moae  is found on Moa, Leti and Romang Islands in the Lesser Sunda Islands. It is darker than subspecies boobook. It was described by Mayr in 1943 from a specimen collected by one H. Kühn in 1902 on Moa. Mayr noted that it had dark reddish upperparts with pronounced barring on wings and tail, larger white spots on scapulars and buff streaks on the nape. The call is similar to those of the Australian subspecies.
N. b. ocellata is found across northern Australia, Western Australia and western South Australia, as well as Savu near Timor. It was described as Athene ocellata by  French biologist Charles Lucien Bonaparte in 1850, from a specimen from Raffles Bay on the Cobourg Peninsula. It is generally lighter-coloured than other mainland boobooks, though occasional dark-plumaged individuals are seen. The face in particular is pale, with feathers of the forehead and lores white with black shafts. Birds from Melville Island are small and generally dark, and were previously classified as a separate subspecies melvillensis by Mathews in 1912. Birds from southwestern Australia north to Tantabiddy on the North West Cape and Glenflorrie on the Ashburton River are relatively dark with more uniform rufous-brown underparts. Mees classified them as a separate subspecies rufigaster. Mayr classified the lightest birds of northern Australia as arida, medium-toned birds as mixta and darker ones macgillivrayi. All these taxa are now regarded as ocellata. Its call is similar to that of the nominate subspecies.
N. b. pusilla is from the southern lowlands of New Guinea, along the Oriomo and Wassi Kusa Rivers, west of the Fly River. Described by Mayr and Canadian zoologist Austin L. Rand in 1935 from a specimen collected in Dogwa, it resembles subspecies ocellata but is smaller.
N. b. remigialis is found on the Kai Islands in the Lesser Sunda Islands. Stresemann described it in 1930 from a specimen collected in 1909. Poorly known, it has been recorded twice more in 1998 and 2010. It has a call more similar to the barking owl, and might be classified as a subspecies of it instead.
Three former subspecies of Ninox boobook have been classified as distinct species since 2017: namely, Rote boobook (Ninox rotiensis), Timor boobook (N. fusca), and Alor boobook (N. plesseni).
Australian boobook