The Symphony No. 6 in A minor by Gustav Mahler is a symphony in four movements, composed in 1903 and 1904, with revisions from 1906. It is sometimes nicknamed the Tragic ("Tragische"), though the origin of the name is unclear.

Gustav Mahler was an Austro-Bohemian Romantic composer, and one of the leading conductors of his generation. As a composer he acted as a bridge between the 19th-century Austro-German tradition and the modernism of the early 20th century. While in his lifetime his status as a conductor was established beyond question, his own music gained wide popularity only after periods of relative neglect, which included a ban on its performance in much of Europe during the Nazi era. After 1945 his compositions were rediscovered by a new generation of listeners; Mahler then became one of the most frequently performed and recorded of all composers, a position he has sustained into the 21st century.