UGG is an American fashion company primarily known for its sheepskin boots, founded in 1978 by Australian surfer Brian Smith in Santa Monica, California. After putting on his pair of Australian sheepskin boots after a chilly late-night surf in Malibu, Smith realized sheepskin boots weren't available in the United States like they were in Australia, giving Smith the idea to create UGG. UGG also sells apparel, accessories, and home textiles.

Sheepskin boots are boots made from sheepskin. The wool on sheepskin has good insulating properties and so such boots are commonly worn when it is cold.