Antoine Tamestit (born 1979) is a French violist. He premiered several contemporary compositions. Tamestit plays the Stradivarius viola Gustav Mahler.

Tamestit was born in Paris. He studied at the Conservatoire de Paris with Jean Sulem, and further with Jesse Levine at Yale University, and with Tabea Zimmermann. He was a BBC Radio 3 New Generation Artist from 2004 to 2006.

He has performed at such venues as the Royal Concertgebouw, the Vienna Musikverein, and Carnegie Hall and with the Santa Cecilia Orchestra in Rome [14 March 2019]. In 2014, he played viola for the recording of Berlioz's Harold en Italie, conducted by Valery Gergiev.

Tamestit premiered several contemporary compositions, including Thierry Escaich's La Nuit des chants, Bruno Mantovani's Concerto pour deux altos et orchestre and Olga Neuwirth's Remnants of songs… an Amphigory and Weariness heals Wounds. In 2015, he premiered Jörg Widmann's Viola Concerto, which was commissioned by him, with the Orchestre de Paris and Paavo Järvi. This concerto depicts Tamestit's skills and character.

Tamestit played chamber music with Emmanuel Ax, Isabelle Faust, Martin Fröst, Leonidas Kavakos, Yo-Yo Ma, Emmanuel Pahud, Francesco Piemontesi, Cédric Tiberghien, Yuja Wang, Jörg Widmann, Shai Wosner, and the Ébène Quartet.

Together with Frank Peter Zimmermann and Christian Poltéra, Tamestit founded the Trio Zimmermann.

He was professor at the Musikhochschule in Cologne, the Conservatoire de Paris, and teaches in masterclasses at the Kronberg Academy.

Tamestit plays on the first viola made in 1672 by Antonio Stradivari, called Gustav Mahler.