The muskox (Ovibos moschatus, in Latin "musky sheep-ox"), also spelled musk ox and musk-ox, plural muskoxen or musk oxen (in Inuktitut: ᐅᒥᖕᒪᒃ, umingmak; in Woods Cree: ᒫᖨᒨᐢ, mâthi-môs, ᒫᖨᒧᐢᑐᐢ, mâthi-mostos), is a hoofed mammal of the family Bovidae. Native to the Arctic, it is noted for its thick coat and for the strong odor emitted by males during the seasonal rut, from which its name derives. This musky odor has the effect of attracting females during mating season. Its Inuktitut name "umingmak" translates to "the bearded one".

Its Woods Cree names "mâthi-môs" and "mâthi-mostos" translate to "ugly moose" and "ugly bison", respectively. Muskoxen primarily live in Greenland and the Canadian Arctic of the Northwest Territories and Nunavut, with reintroduced populations in the American state of Alaska, the Canadian territory of Yukon, and Siberia, and an introduced population in Norway, part of which emigrated to Sweden, where a small population now lives.