Jean Sibelius (December 8, 1865 – September 20, 1957) was a Finnish composer of classical music. Sibelius is considered to be one of the most popular composers of the late 19th and early 20th century. His music and genius have also played an important role in forming of the Finnish national identity.

Sibelius was born into a Swedish-speaking family in Hämeenlinna in the Russian Grand Duchy of Finland. He was given the name Johan Julius Christian Sibelius. He was known as Janne to his family, but during his student years he started using a French form of the name, Jean. His family consciously decided to send him to an important Finnish language school. He attended The Hämeenlinna Normal-lycée from 1876 to 1885. This should be seen as part of the larger rise of the Fennoman movement, an expression of Romantic Nationalism which was to become a crucial part of Sibelius' artistic output and politics.

Some of his most famous compositions are Finlandia, Valse Triste, the violin concerto, the Karelia Suite and The Swan of Tuonela (a movement from his Lemminkäinen Suite). He also wrote many other works, including pieces inspired by the Kalevala, seven symphonies, over 100 songs for voice and piano, incidental music for 13 separate plays, an opera (Jungfrun i tornet, which remains unpublished), chamber music (including a piece for a string quartet), piano music, 21 separate publications of choral music, and Masonic ritual music.

The Finnish graphic designer Erik Bruun used Jean Sibelius as the motiv for the 100 markka note in Finland's final markka series.