Vilhjalmur Stefansson (November 3, 1879 – August 26, 1962) was an Icelandic Arctic explorer and ethnologist.

Stefansson was an extremely well-known explorer in his lifetime. Late in life, through his affiliation with Dartmouth College (he was Director of Polar Studies), he became a major figure in the establishment of the US Army's Cold Regions Research and Engineering Laboratory (CRREL) in Hanover, New Hampshire. CRREL-supported research, often conducted in winter on the forbidding summit of Mount Washington, has been key to developing materiel and doctrine to support alpine conflict.

Stefansson's personal papers and collection of arctic artifacts are maintained and available to the public at the Dartmouth College Library .