The Owls are the order Strigiformes, comprising 200 extant bird of prey species. Most are solitary and nocturnal with some exceptions (e.g. the Northern Hawk Owl). Owls hunt mostly small mammals, insects, and other birds though a few species specialize in hunting fish. They are found in all regions of the Earth except Antarctica, most of Greenland and some remote islands. Though owls are typically solitary, the literary collective noun for a group of owls is a parliament.

Living owls are divided into two families: the typical owls, Strigidae; and the barn-owls, Tytonidae.

Owls have large forward-facing eyes and ear-holes, a hawk-like beak, a flat face, and usually a conspicuous circle of feathers, a facial disc, around each eye. Although owls have binocular vision, their large eyes are fixed in their sockets, as with other birds, and they must turn their entire head to change views. Most birds of prey sport eyes on the sides of their heads, but the stereoscopic nature of the owl's forward-facing eyes permits a greater sense of depth perception necessary for low-light hunting.

Owls are farsighted and are unable to see anything clearly within a few centimeters of their eyes. Caught prey can be felt by owls with the use of filoplumes, which are small hair-like feathers on the beak and feet that act as "feelers". Their far vision, particularly in low light, is exceptionally good. Contrary to popular myth, an owl cannot turn its head completely backwards. It can turn its head 135 degrees in either direction; it can thus look behind its own shoulders, with a total 270-degree field of view.

The smallest owl is the Elf Owl (Micrathene whitneyi), at as little as 31 g (1.1 oz) and 13.5 cm (5.3 inches). Some of the pygmy owls are scarcely larger. The largest owls are two of the eagle owls; the Eurasian Eagle Owl (Bubo bubo) and Blakiston's Fish Owl (Bubo blakistoni)—which may reach a size of 60 – 71 cm (28.4 in) long, have a wingspan of almost 2 m (6.6 ft), and an average weight of nearly 4.5 kg (10 lb).

Africa
Ancient Egyptians used a representation of an owl for their hieroglyph for the sound m. They would often draw this hieroglyph with its legs broken to keep this bird of prey from coming to life.

Among the Kikuyu of Kenya it was believed that owls were harbingers of death. If one saw an owl or heard its hoot, someone was going to die. In general, owls are viewed as harbingers of bad luck, ill health, or death. The belief is widespread even today.

The Americas
The feathers of owls are often used in connection with art and ritual. However, in the United States, as with eagle feathers, the possession of owl feathers as religious objects is regulated by federal law (e.g. The Migratory Bird Treaty Act of 1918 and Title 50 Part 22 Code of Federal Regulations).

In the culture of the Uto-Aztec tribe, the Hopi, taboos surround owls, which are associated with sorcery and other evils. The Aztecs and Maya, along with other Natives of Mesoamerica, considered the owl a symbol of death and destruction. In fact, the Aztec god of death, Mictlantecuhtli, was often depicted with owls. There is an old saying in Mexico that is still in use: Cuando el tecolote canta, el indio muere ("When the owl cries/sings, the Indian dies"). The Popol Vuh, a Mayan religious text, describes owls as messengers of Xibalba (the Mayan "Place of Fright"). The belief that owls are messengers and harbingers of the dark powers is also found among the Hocagara (Winnebago) of Wisconsin. When in earlier days the Hocagara committed the sin of killing enemies while they were within the sanctuary of the chief's lodge, an owl appeared and spoke to them in the voice of a human, saying, "From now on the Hocagara will have no luck." This marked the beginning of the decline of their tribe. An owl appeared to Glory of the Morning, the only female chief of the Hocak nation, and uttered her name. Soon afterwards she died. People often allude to the reputation of owls as bearers of supernatural danger when they tell misbehaving children, "the owls will get you."

The Moche people of ancient Peru worshipped the animal and often depicted owls in their art.
In pre-Columbian Florida, the owl was one of the sacred totems of the Timucua people. In 1955, a carved owl totem was discovered buried in the St. Johns River.
Asia
In Japanese culture, owls are seen as either negative or positive symbols depending on species. Sometimes owls are seen as divine messengers of the gods, while Barn or Horned owls are perceived as demonic figures.

In India, a white owl is considered companion and vahana (Vehicle of god/goddess) of Lak?mi, the goddess of wealth, and therefore a harbinger of prosperity. In many Indian languages the word owl is used as an insult, usually in the connotation of calling someone a fool.

The demoness Lilith is thought to have been associated with (screech) owls as well, by way of the KJV translation of the passage in Isaiah 34:14. Prior to the rise of Islam, owls were considered bad omens and associated with evil spirits in most Middle Eastern pagan traditions. In modern times, although such superstitions are less prevalent, owls are still popularly considered "evil" because of their fierce appearance.

Europe
In Greek mythology, the owl, and specifically the Little Owl, was often associated with the goddess Athena, a bird goddess who became associated with wisdom, the arts, and skills, and as a result, owls also became associated with wisdom. They are the unofficial mascot of the high-IQ society Mensa.
The Romans, in addition to having borrowed the Greek associations of the owl (see Owl of Minerva), also considered owls to be funerary birds, due to their nocturnal activity and often having their nests in inaccessible places. As a result, seeing an owl in the daytime was considered a bad omen. For example, in Book 12 of Virgil's Aeneid, an owl appears before Turnus toward the end of his battle with Aeneas, prefiguring his death, and "a strange, numbing dread / Washed through Turnus' body; his hair / Bristled with fear; his voice stuck in his throat." The vampiric strix of Roman mythology was in part based on the owl.

In France, a difference is made between hiboux, eared owls, which are considered symbols of wisdom, and chouettes, earless owls, which are considered birds of an omen.