César-Auguste Jean-Guillaume Hubert Franck (French pronunciation: ​[sezaʁ oɡyst ʒɑ̃ ɡijom ybɛʁ fʁɑ̃k]; 10 December 1822 – 8 November 1890) was a French Romantic composer, pianist, organist, and music teacher born in modern-day Belgium.

He was born in Liège (which at the time of his birth was part of the United Kingdom of the Netherlands). He gave his first concerts there in 1834 and studied privately in Paris from 1835, where his teachers included Anton Reicha. After a brief return to Belgium, and a disastrous reception of an early oratorio Ruth, he moved to Paris, where he married and embarked on a career as teacher and organist. He gained a reputation as a formidable musical improviser, and travelled widely within France to demonstrate new instruments built by Aristide Cavaillé-Coll.

In 1858, he became organist at the Basilica of St. Clotilde, Paris, a position he retained for the rest of his life. He became professor at the Paris Conservatoire in 1872; he took French nationality, a requirement of the appointment. After acquiring the professorship, Franck wrote several pieces that have entered the standard classical repertoire, including symphonic, chamber, and keyboard works for pipe organ and piano. As a teacher and composer he had a vast following of composers and other musicians. His pupils included Ernest Chausson, Vincent d'Indy, Henri Duparc, Guillaume Lekeu, Albert Renaud, Charles Tournemire and Louis Vierne.