Ovis dalli, also known as the Dall sheep or thinhorn sheep, is a species of wild sheep native to northwestern North America. Ovis dalli contains two subspecies: Ovis dalli dalli and Ovis dalli stonei. O. dalli live in mountainous alpine habitats distributed across northwestern British Columbia, the Yukon, Northwest Territories and Alaska. They browse a variety of plants such as grasses, sedges and even shrubs such as willow, during different times of the year. They also acquire minerals to supplement their diet from mineral licks. Like other Ovis species, the rams engage in dominance contests with their horns.

Ovis is a genus of mammals, part of the Caprinae subfamily of the ruminant family Bovidae. Its seven highly sociable species are known as sheep or ovines. Domestic sheep are members of the genus, and are thought to be descended from the wild mouflon of central and southwest Asia.