The McKay's Bunting, Plectrophenax hyperboreus, is a passerine bird in the bunting family Emberizidae, a family now recognized by ornithologists as separate from the finches Fringillidae. It is most closely related to the Snow Bunting P. nivalis. There is only speculation about hybridization, no hybrids between the two species have been confirmed. The Plectrophenax buntings are nested within the Calcarius clade; their closest relatives are the longspurs.
It 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.
The population of this species is estimated at less than 6,000 individuals. Although under no immediate threat, it is susceptible to devastation by any introduced rats, weasels or foxes, as well as rising sea levels due to climate change.
The name of this bird honours the American naturalist Charles McKay.