The Sotho-Tswana, also known as the Sotho or Basotho, although the term is now closely associated with the Southern Sotho peoples are a meta-ethnicity of Southern Africa. They are a large and diverse group of people who speak Sotho-Tswana languages. The group is predominantly found in Botswana, Lesotho, South Africa, and the western part of Zambia. Smaller groups can also be found in Namibia^{[citation needed]} and Zimbabwe.

The Sotho-Tswana people would have diversified into their current arrangement during the course of the 2nd millennium, but they retain a number of linguistic and cultural characteristics that distinguish them from other Bantu-speakers of southern Africa. These are features such as totemism/diboko a pre-emptive right of men to marry their maternal cousins, and an architectural style characterized by a round hut with a conical thatch roof supported by wooden pillars on the outside. Other major distinguishing features included their dress of skin cloaks and a preference for dense and close settlements, as well as a tradition of large-scale building in stone.

The group mainly consists of four clusters: the Southern Sotho (Sotho), the Northern Sotho (which consists of the Bapedi, the Balobedu and others), the Lozi, the Tswana and the Kgalakgadi. A fifth cluster is sometimes referred to as the Eastern Sotho and consists of the Pulana, Kgolokwe, Pai, and others. The Sotho-Tswana are said to contain some Khoe-San ancestry with levels as high as >20%.

The Sotho-Tswana ethnic group derives its name from the people who belong to the various Sotho and Tswana clans that live in southern Africa. Historically, all members of the group were referred to as Sothos; the name is now exclusively applied to speakers of Southern Sotho who live mainly in Lesotho and the Free State province in South Africa, while Northern Sotho is reserved for Sotho speakers that inhabit north-eastern South Africa, predominantly in Limpopo.

The term Basotho may have originated as a derogatory term used by the Swazi to refer to the Pedi in the 1400s. The Swazi called the Bapedi "Abashuntu" because they wore breechcloths made of animal skins tied in knots to cover their private parts. The word "Abashuntu" comes from the verb "uku shunta," which means "to make a knot."

Despite the derogatory origins of the term, the Pedi adopted it with pride. They took the name with pride. Other Sotho-speaking groups who also wore breechcloths adopted the term as well, and it eventually came to be used to refer to all Sotho people.

The Basotho name is thought to be derived from the word "sootho", "brown" , which means the ones with dark/brown melanin. "Ba sootho" directly translates to "They are brown".

The use of the word has always been part of the vocabulary of the Sotho-Tswana nation. The word became ascribed to a specific people due to regional conflicts: different Bantu clans split from their ancestor clans and took the name of their leader as their identity, but naturally, in essence, every Batho/Bantu people is a Mosotho.