The snow bunting is a passerine bird in the family Calcariidae. It is an Arctic specialist, with a circumpolar Arctic breeding range throughout the northern hemisphere. There are small isolated populations on a few high mountain tops south of the Arctic region, including the Cairngorms in central Scotland and the Saint Elias Mountains on the southern Alaska-Yukon border, as well as the Cape Breton Highlands. The snow bunting is the most northerly recorded passerine in the world.

Calcariidae is a small family of passerine birds. It includes longspurs and snow buntings. There are six species in three genera worldwide, found mainly in North America and Eurasia. They are migratory and can live in a variety of habitats including grasslands, prairies, tundra, mountains, and beaches.