The Symphony No. 6 in D minor, Op. 104, is a four-movement work for orchestra written from 1914 to 1923 by the Finnish composer Jean Sibelius.

Jean Sibelius was a Finnish composer of the late Romantic and early-modern periods. He is widely regarded as his country's greatest composer, and his music is often credited with having helped Finland develop a stronger national identity when his country was struggling from several attempts at Russification in the late 19th century.