The Tatar confederation (Chinese: 塔塔兒; Old Turkic: 𐱃𐱃𐰺, romanized: tatar; Middle Mongolian: ᠲᠠᠲᠠᠷ) was one of the five major tribal confederations (khanlig) in the Mongolian Plateau in the 12th century.

The name "Tatar" was possibly first transliterated in the Book of Song as 大檀 Dàtán (MC: *da^H-dan) and 檀檀 Tántán (MC: *dan-dan) which the book's compilers stated to be other names of the Rourans; Book of Song and Book of Liang connected Rourans to the earlier Xiongnu while the Book of Wei traced the Rouran's origins back to the Donghu, who were of Proto-Mongolic origin.

Xu proposed that "the main body of the Rouran were of Xiongnu origin" and Rourans' descendants, namely Da Shiwei (aka Tatars), contained Turkic-speaking Xiongnu elements to a great extent. Even so, the language of the Xiongnu is still unknown, and Chinese historians routinely ascribed Xiongnu origins to various nomadic groups, yet such ascriptions do not necessarily indicate the subjects' exact origins: for examples, Xiongnu ancestry was ascribed to Turkic-speaking Göktürks and Tiele as well as Para-Mongolic-speaking Kumo Xi and Khitans.

The first precise transcription of the Tatar ethnonym was written in Turkic on the Orkhon inscriptions, specifically, the Kul Tigin (CE 732) and Bilge Khagan (CE 735) monuments as 𐰆𐱃𐰔⁚𐱃𐱃𐰺⁚𐰉𐰆𐰑𐰣, Otuz Tatar Bodun, 'Thirty Tatar clan' and 𐱃𐰸𐰔⁚𐱃𐱃𐰺, Tuquz Tatar, 'Nine Tatar' referring to the Tatar confederation.

In historiography, the Proto-Mongolic Shiwei tribes are associated with the Dada or identified with specifically the Thirty Tatars. As for the Nine Tatars, Ochir (2016) considers them to be Mongolic and proposes that this tribe apparently formed in Mongolia during the 6th–8th centuries, that their ethnogenesis involved Mongolic people as well as Mongolized Turks who had ruled them; later on, Nine Tatars participated in the ethno-cultural development of the Mongols. Rashid al-Din Hamadani named nine tribes: Tutukliud (Tutagud), Alchi, Kuyn, Birkuy, Terat, Tamashi, Niuchi, Buyragud, and Ayragud, living in the eastern steppe and the Khalkhyn Gol's basin during the second half of 12th century. Golden (1992) proposes that that Otuz "thirty" denoted thirty clans and Toquz "nine" possibly denoted nine tribes of the Tatar confederation.

Tatars were proposed to dwell in Northeastern Mongolia and around Lake Baikal, or between Manchuria and Lake Baikal.

Toquz-Tatars and Otuz-Tatars from the Orkhon inscriptions are proposed to be Mongolic speakers (e.g. by sinologists Paul Pelliot, and Ulrich Theobald, turkologist Peter Benjamin Golden, Altaist Volker Rybatzki, etc.). On the other hand, they were proposed to be Turkic speakers (e.g. by Encyclopedia Britannica or Kyzlasov apud Sadur 2012). Additionally, Encyclopedia Britannica proposes that Tatars were possibly related to the Cumans and Kipchaks.

Ochir (2016) proposes that Mongolic and Mongolized Turkic peoples participated in the ethnogenesis of the Nine Tatars, whom Ochir considers to be Mongolic.