Junglefowl are the only four living species of bird from the genus Gallus in the bird order Galliformes, and occur in parts of South and Southeast Asia. One of the species in this genus, the red junglefowl, is of historical importance as the direct ancestor of the domestic chicken, although the grey junglefowl, Sri Lankan junglefowl and green junglefowl are likely to have also been involved. The Sri Lankan junglefowl is the national bird of Sri Lanka. They diverged from their common ancestor about 4–6 million years ago. Although originating in Asia, remains of junglefowl bones have also been found in regions of Chile, which date back to 1321–1407 CE, providing evidence of possible Polynesian migration through the Pacific Ocean.

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.