The Sioux ( /ˈsuː/) are Native American and First Nations people in North America. The term can refer to any ethnic group within the Great Sioux Nation or any of the nation's many language dialects. The Sioux comprise three major divisions based on Siouan dialect and subculture:

Today, the Sioux maintain many separate tribal governments scattered across several reservations, communities, and reserves in the Dakotas, Nebraska, Minnesota, and Montana in the United States; and Manitoba and southern Saskatchewan in Canada.