String Quartet No. 6 may refer to:
String Quartet No. 6 (Babbitt) by Milton Babbitt String Quartet No. 6 (Bartók) by Béla Bartók String Quartet No. 6 (Beethoven) by Ludwig van Beethoven String Quartet No. 6 (Diamond) by David Diamond String Quartet No. 6 (Dvořák) by Antonín Dvořák String Quartet No. 6 (Ferneyhough) by Brian Ferneyhough String Quartet No. 6 (Halffter) by Cristóbal Halffter String Quartet No. 6 (Hill) by Alfred Hill String Quartet No. 6 (McCabe), Silver Nocturnes, by John McCabe String Quartet No. 6 (Maconchy) by Elizabeth Maconchy String Quartet No. 6 (Mendelssohn) by Felix Mendelssohn String Quartet No. 6 (Milhaud), Op. 77, by Darius Milhaud String Quartet No. 6 (Mozart) by Wolfgang Amadeus Mozart String Quartet No. 6 (Porter) by Quincy Porter String Quartet No. 6 (Rihm) by Wolfgang Rihm String Quartet No. 6 (Schubert) by Franz Schubert String Quartet No. 6 (Shostakovich) by Dmitri Shostakovich String Quartet No. 6 (Spohr) by Louis Spohr String Quartet No. 6 (Villa-Lobos) by Heitor Villa-Lobos