Sesotho is a Southern Bantu language, belonging to the Niger–Congo language family within theSotho-Tswana branch of Zone S (S.30).

"Sotho" is also the name given to the entire Sotho-Tswana group, in which case Sesotho proper is called "Southern Sotho". Within the Sotho-Tswana group, Sesotho proper is most closely related toLozi (Silozi), with which it forms the Sesotho-Lozi group within Sotho-Tswana.

The Northern Sotho group is geographical, and includes a number of dialects also closely related to Sesotho-Lozi. Northern Sotho language. Tswana is also known as "Western Sesotho".

The Sotho-Tswana group is in turn closely related to the other Southern Bantu languages, including the Venḓa, Tsonga, Tonga, and Nguni languages, and possibly[clarification needed] also theMakua (zone P) languages of Tanzania and Mozambique.

Sotho is a tribal suffix, i.e. the name of the Sotho people or Basotho, while Sesotho is the term for the "language of the Basotho". Use of Sesotho rather than "Sotho language" in English has seen increasing use since the 1980s, especially in South African English and in Lesotho.