Klaus Maetzl (1941 – 4 May 2016) was an Austrian violinist, noted as a founder of the Alban Berg Quartet. He studied at the University of Music and Performing Arts in Vienna with , and studied further with Max Rostal. From 1967 to 1970, he was concertmaster of the Vienna Symphony. In 1970, Maetzl was a founder member, with Günter Pichler, Hatto Beyerle and Valentin Erben, of the Alban Berg Quartet, in which he played second violin; he remained with the quartet until 1978. From 1982 he was a member of the Vienna Chamber Ensemble.