Pēteris Vasks (born April 16, 1946) is a Latvian composer.

Vasks was born in Aizpute, Latvia, to a family of a Baptist pastor. He trained as a double-bass player, and played in several Latvian orchestras before entering the State Conservatory in Vilnius in the neighboring Lithuania to study composition, as he was prevented from doing this in Latvia due to Soviet repressive policy toward Baptists. He started to become known outside Latvia in the 1990s.

Initially, Vasks' style owed much to the aleatoric experiments of Witold Lutosławski, Krzysztof Penderecki and George Crumb. Later works included elements of Latvian folk music, such as his gentle and pastoral cor anglais concerto (1989). His works are generally extremely clear and communicative, with a solid and muscular sense of harmony. Lyrical passages may be followed by agitated dissonances, or interrupted by sombre sections with a march-like feel. He made extensive use of minimalist techniques as well, but never became a slave to any particular method.

Vasks feels strongly about environmental issues, and a sense of nature both pristine and destroyed can be found in many of his works, such as the String Quartet No. 2 (1984). Other important works include Cantabile (1979) and Musica dolorosa (1984). He has written five string quartets, the fourth of which (2003) was written for the Kronos Quartet.

Vasks was the recipient of the Vienna Herder Award in 1996 and the Latvian Grand Music Award in 1997, the latter for his violin concerto Tālā Gaisma (1996-7). His important works also include "Viatore", Symphony #2, "Music for a Deceased Friend" et al.