McKay's bunting (Plectrophenax hyperboreus) is a passerine bird in the longspur family Calcariidae. It is most closely related to the snow bunting (P. nivalis). Hybrids between the two species have been observed, leading some authorities to treat McKay's as a subspecies of snow bunting. As the Plectrophenax buntings are nested within the Calcarius clade, their closest relatives are the longspurs. McKay's bunting breeds on two islands in the Bering Sea, St. Matthew and Hall islands, and winters on the western coast of the U.S. state of Alaska.
This species closely resembles snow bunting in all plumages, but is whiter overall. The breeding plumage of the male is almost purely white, with only small areas of black on the wingtips and tail. The breeding female has a streaked back. Non-breeding birds also have warm brown patches on cheeks, crown, and the sides of the neck.