The morepork (Ninox novaeseelandiae), better known as the morepork owl, and also known by numerous other onomatopoeic names (such as boobook, mopoke or ruru), is a smallish, brown owl species found in New Zealand, and to the northwest, on Norfolk Island, an Australian territory. It was also, formerly, found on Lord Howe Island. Three subspecies of the morepork are recognised, one of which is extinct and another that exists only as a hybrid population.

First described by Johann Friedrich Gmelin in 1788, the morepork was thought to be the same species as the Australian boobook (N. boobook), native to Australia, Timor-Leste and New Guinea, something that endured for more than two hundred years, until 1999. Similarly, it was also considered the same as the Tasmanian boobook (N. leucopsis) until 2022.

The morepork has dark-brown plumage with prominent pale spots and golden-yellow eyes. Like most owls, the species is generally nocturnal, though may be crepuscular at times (or active at dawn and dusk), retiring to roost in secluded spots within the branches of trees. The morepork feeds on larger insects and small vertebrates, hunting by pouncing on them from tree perches. As with all owls, the morepork has supreme night vision and excellent hearing, able to locate a tiny lizard or rodent from many metres above and away. They then stealthily approach their targeted prey with near-silent flight, without flapping their wings, the prey often not even aware they are being pursued.

The International Union for Conservation of Nature (IUCN) has assessed the morepork's population and its potential for decline, and ranked the species as being of least concern (not currently at-risk), owing to its presently large range and apparently stable population.

The morepork is 26 to 29 cm (10 to 11.5 in) long, with the female slightly larger than the male. Females are slightly heavier at 170–216 g (6.0–7.6 oz) compared with the male's 140–156 g (4.9–5.5 oz). The morepork has generally dark brown head and upperparts, with pale brown spots on head and neck and white markings on the rest of the upperparts, with a pale yellow-white supercilium (eyebrow), dark brown ear coverts, and buff cheeks. The eyes are yellow to golden-yellow. The feathers of the chin and throat are buff with dark brown shafts. The feathers of the underparts are mostly dark brown with buff and white spots and streaks, with the larger markings on the belly making it look paler overall. The upper tail is dark brown with lighter brown bars. The cere and bill is pale blue-grey with a black cutting edge. The feet are orange or yellow with blackish claws.

Young moreporks do not attain adult plumage properly until their third or fourth year. The tips of juvenile's feathers are white and fluffy, remnants of the nestlings' down. These are worn away over time, persisting longest on the head. The feathers of the head, neck, and underparts are fluffier overall. Their plumage is a darker and more greyish brown overall than that of adults.