'''Jean Sibelius''' (; ), born '''Johan Julius Christian Sibelius''': only in the 1990s was it discovered that Sibelius' original first names (at christening) were '''Johan Christian Julius'''; he himself used the order '''Johan Julius Christian''', and that is present in most sources. (8 December 186520 September 1957), was a Finnish violinist and composer of the late Romantic and early-modern periods. Widely recognized as his country's national composer, Sibelius is often credited for helping the Finns to develop a feeling of national identity in their struggle for independence.

The core of his oeuvre is his set of seven symphonies which, like his other major works, continue to be performed and recorded in his home country and internationally. In addition to his symphonies, Sibelius's best-known compositions include ''Finlandia'', the ''Karelia Suite'', ''Valse triste'', the Violin Concerto, the choral symphony ''Kullervo'', and ''The Swan of Tuonela'' (from the ''Lemminkäinen Suite''). Other works include pieces inspired by the Finnish national epic, the ''Kalevala'', over a hundred songs for voice and piano, incidental music for numerous plays, the opera ''Jungfrun i tornet'' (''The Maiden in the Tower''), chamber music, piano music, Masonic ritual music, and 21 publications of choral music. Throughout his career, the composer found inspiration in nature and Nordic mythology, especially the heroic legends of the national epic, the ''Kalevala''.

Sibelius composed prolifically until the mid-1920s but after completing his Seventh Symphony (1924), the incidental music to ''The Tempest'' (1926), and the tone poem ''Tapiola'' (1926), he failed to produce any major works in his last thirty years, a stunning and perplexing decline commonly referred to as 'The Silence of Järvenpää', the location of his home. Although he is reputed to have stopped composing, he attempted to continue writing, including abortive efforts on an eighth symphony. In later life, he wrote Masonic music and re-edited some earlier works while retaining an active but not always favourable interest in new developments in music.

The Finnish 100 mark bill featured his image until 2002 when the euro was adopted. Since 2011, Finland has celebrated a Flag Day on 8 December, the composer's birthday, also known as the "Day of Finnish Music". In 2015, the 150th anniversary of the composer's birth, a number of special concerts and events have been planned, especially in the city of Helsinki.