The Hornbills (Bucerotidae) are a family of 59 species found in tropical and sub-tropical Africa and Asia. They are characterized by a long, down-curved bill which is frequently brightly-coloured and sometimes has a casque on the upper mandible. Both the common English and the scientific name of the family refer to the shape of the bill, "buceros" being "cow horn" in Greek.

Hornbills are the only birds in which the first two neck vertebrae (the axis and atlas) are fused together; this probably provides a more stable platform for carrying the bill. The family is omnivorous, feeding on fruit and small animals. They are monogamous breeders nesting in natural cavities in trees and sometimes cliffs. A number of species of hornbill are threatened with extinction, mostly insular species with small ranges.

The most distinctive feature of the hornbills is the heavy bill, supported by powerful neck muscles as well as by the fused vertebrae. The large bill assists in fighting, preening, and constructing the nest, as well as catching prey. A feature unique to the hornbills is the casque, a hollow structure that runs along the upper mandible. In some species it is barely perceptible and appears to serve no function beyond reinforcing the bill. In other species it is quite large, is reinforced with bone, and has openings between the hollow centre allowing serve as a resonator for calls. In the Helmeted Hornbill the casque is not hollow but is filled with ivory and is used as a battering ram used in dramatic aerial jousts.

Hornbills possess binocular vision, although unlike most birds with this type of vision the bill intrudes on their visual field. This allows them to see their own bill tip and aids in precision handling of food objects with their bill. The eyes are also protected by large eyelashes which act as a sunshade.

Hornbills are omnivorous birds, eating fruit, insects and small animals. They cannot swallow food caught at the tip of the beak as their tongues are too short to manipulate it, so they toss it back to the throat with a jerk of the head. While both open country and forest species are omnivorous, species that specialise in feeding on fruit are generally found in forests while the more carnivorous species are found in open country. Forest living species of hornbills are considered to be important seed dispersers. In some instances hornbills defend a fixed territory.Territoriality is related to diet; fruit sources are often patchily distributed and require long distance travel in order to find, thus species that specialise in fruit are less territorial.