The Mackenzie Valley wolf (Canis lupus occidentalis) also known as the Canadian timber wolf is perhaps the largest subspecies of gray wolf in North America.

In 1992, this wolf was re-classified as Canis lupus occidentalis, the Mackenzie Valley wolf, common with wolves in Alaska and Western Canada.

Dutch breeder Leendert Saarloos started crossbreeding a German Shepherd male to a female Mackenzie Valley Wolf (Canis lupus occidentalis).

The cranium is about twice the length of that of a modern Alaskan brown bear (Ursus arctos middendorffi), but with a lower length-to-width ratio, and about triple the length of an American wolf's (Canis lupus occidentalis).