Pheasants are birds of several genera within the family Phasianidae in the order Galliformes. Although they can be found all over the world in introduced populations, the pheasant genera native range is restricted to Eurasia. The classification "pheasant" is paraphyletic, as birds referred to as pheasants are included within both the subfamilies Phasianinae and Pavoninae, and in many cases are more closely related to smaller phasianids, grouse, and turkey than to other pheasants.

Galliformes is an order of heavy-bodied ground-feeding birds that includes turkeys, chickens, quail, and other landfowl. Gallinaceous birds, as they are called, are important in their ecosystems as seed dispersers and predators, and are often reared by humans for their meat and eggs, or hunted as game birds.