The muskox (Ovibos moschatus, musk ox) is an Arctic mammal of the family Bovidae, noted for its thick coat and for the strong odor emitted by males, from which its name derives. This musky odor is used to attract females during mating season. Muskoxen primarily live in Arctic North America and Greenland, with small introduced populations in Sweden, Siberia and Norway.

The muskox, or its ancestor, is believed to have migrated to North America between 200,000 and 90,000 years ago, during the Pleistocene period, when it was a contemporary of the woolly mammoth. It is thought that the muskox was able to survive the last ice age (Wisconsin glaciation) by finding ice-free areas away from prehistoric peoples. The muskox gradually moved across North America and arrived in Greenland during the late Holocene.

As members of the subfamily Caprinae of the family Bovidae, muskoxen are more closely related to sheep and goats than to oxen, but are in their own genus, Ovibos (Latin: "sheep-ox"). Both sexes have long curved horns. Muskoxen stand 1.2 m (4 ft) high at the shoulder on average, with females measuring 135 to 200 cm (4.4 to 6.6 ft) in length, and males 200 to 250 cm (6.6 to 8.2 ft). Adults, on average, weigh 285 kg (600 lb) and range from 180 to 400 kg (400 to 900 lb). Their life expectancy is 12–20 years. The thick coat and large head often suggests a larger animal than the muskox truly is, but heavy zoo-kept specimens have weighed up to 650 kilograms (1,400 lb). Their coat, a mix of black, gray, and brown, includes long guard hairs that almost reach the ground. Rare "white muskoxen" have been spotted in the Queen Maud Gulf Bird Sanctuary. Muskoxen are occasionally domesticated for wool, meat and milk.^{[citation needed]} The wool, qiviut, is highly prized for its softness, length, and insulation value. Prices for yarn range between $40 and $80 per ounce (28 g).