The Keller Quartet specializes in contemporary music and especially in programs that juxtapose contemporary and traditional repertory. In the recording studio, the group has had a long association with the ECM label.

The Keller Quartet was formed in 1987 by violinists András Keller and Zsófia Környei, violist Gábor Homoki, and cellist Otto Kértész, all of whom were students at the Franz Liszt Music School in Budapest. Kértész was later replaced by László Fenyö, but otherwise, the group's membership has remained stable. Keller was a student of composer and pianist György Kurtág, and the group went on to work closely with Kurtág on several projects. In 1990, within a four-week span, the quartet won the Evian International String Quartet Competition and the second Borciani International Competition, and the group's career was launched. The Keller Quartet has performed in major European capitals, as well as at such top British venues as Wigmore Hall and the Royal Albert Hall. The group has been especially visible at festivals, including the venerable events in Salzburg and Montreux. The group is committed to new music and generally performs two or three new works each year, often combining traditional and contemporary repertory in unusual programs such as "Bach/Kurtág," in which works of the latter are interspersed among the movements of Bach's The Art of Fugue.

The Keller Quartet made its recording debut in 1995 on the Apex label with a cycle of Bartók's string quartets. The group has recorded mostly for the ECM label in its New Series, issuing a program of quartets by the seemingly divergent György Ligeti and Samuel Barber there in 2013. The quartet has also recorded Romantic repertory, releasing a cycle of Tchaikovsky's quartets on Apex in 2009. In 2021, the Keller Quartet joined guitarist Ferenc Snétberger for the recital album Hallgató on ECM. ~ James Manheim, Rovi