The Léner String Quartet, sometimes written the Lehner String Quartet, was a string quartet of Hungarian origin, founded in Budapest in 1918, which for most of its pre-war career operated in or from London. They appeared at the Royal Albert Hall, London on three occasions between 1922 and 1926. They also performed in New York, Amsterdam, and elsewhere in Europe. The Léner made the first complete recorded cycle of Beethoven quartets.

Jenö Léner was born at Szabadka, Hungary (later annexed to Yugoslavia), on 24 June 1894. He studied at the Royal High School for Music in Budapest. He founded the quartet in 1918 and was its leader.

The Léner Quartet recorded extensively during the 1920s and 1930s for Columbia Records, a partnership which received a strong impetus from the centenary of Beethoven's death in 1927, when a core of the Beethoven quartets were recorded or begun (L series). This was followed up in 1928 with the Schubert centenary, for which the Léner recorded the Octet. The LX prefix records below were mainly issued between 1933 and 1936.