The Phasianinae are a subfamily of the pheasant family (Phasianidae) of landfowl, the order Galliformes. The subfamily includes true pheasants, tragopans, grouse, turkey and similar birds. Although this subfamily was considered monophyletic and separated from the partridges, francolins, and Old World quails (Perdicinae) till the early 1990s, molecular phylogenies have shown that this placement is paraphyletic. For example, some partridges (genus Perdix) are more closely affiliated to pheasants, whereas Old World quails and partridges from the genus Alectoris are closer to junglefowls. There are two clades in the Phasianinae: the erectile clade and the non-erectile clades. Both clades are believed to have diverged during the early Oligocene, about 30 million years ago.

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.