The Barn Owl (Tyto alba) or, to distinguish it from relatives, Common Barn Owl, is an owl in the barn owl family Tytonidae. This is one of the two groups of owls, the other being the typical owls Strigidae. Any member of the family Tytonidae is sometimes referred to as a barn owl. The Barn Owl is the most widely distributed species of Tytonidae, and one of the most widespread species of any bird.

This is a pale, long-winged, long-legged owl, 33–39 cm in length with an 80–95 cm wingspan. Its head and upperparts are buff, and the underparts are white. The face is heart shaped.

It has an effortless wavering flight as it quarters pastures or similar hunting grounds. Alternative names often refer to the appearance, white underparts, or eerie, silent flight, including Monkey-faced Owl, Ghost Owl, Church Owl, Golden Owl, Rat Owl and Stone Owl.

In the US it is incorrectly sometimes called Screech Owl because the Barn Owl has a notable shreee scream, ear-shattering at close range. They also hiss like snakes. When captured or cornered, they throw themselves on their backs and flail with sharp-taloned feet, an effective defence. Contrary to popular belief, they do not make the call "tu-whit to-whoo" (which is made by the Tawny Owl).

Barn Owls occur worldwide, on every continent except Antarctica. They are absent from large areas of Asia, the Sahara Desert and New Zealand. These are birds of open country such as farmland, preferring to hunt along the edges of woods.

Barn Owls feed mostly on rodents. These include rats, mice, gophers, shrews, moles, and voles. Each Barn Owl may consume between one to seven rodents per night; a nesting pair and their young can eat thousands of rodents per year.

The Barn Owl flies silently. Its ears are placed asymmetrically for maximum hearing, so the owls do not require sight to hunt. They can target and dive down to sink their talons through snow, grass or brush and seize rodents with deadly accuracy. Compared to other owls of similar size, the Barn Owl has a much higher metabolic rate, requiring relatively more food. Pound for pound, they consume more rodent pests than possibly any other creature. This makes the Barn Owl one of the most economically valuable wildlife animals to farmers. Farmers find these owls more effective than poisons, and they often encourage Barn Owls to stay around by providing nest sites.They are fairly sedentary and nocturnal or crepuscular.

Barn Owls are relatively common throughout most of their range but they are rare in Britain. The most recent survey of their numbers in the UK put their population at around 4400 breeding pairs. In the US, Barn Owls are listed as endangered in 7 Midwestern states.