Jacques Chailley (24 March 1910 in Paris – 21 January 1999 in Montpellier) was a 20th-century French musicologist and composer.
His mother was the pianist Céliny Chailley-Richez (1884–1973), his father the cellist Marcel Chailley (1881–1936). Adolescent, he was a boarder at the Fontgombault Abbey (Indre) where he learned to play the organ and learned about choir directing. At the age of 14, he composed a four-voice Domine non sum dignus.
He received a classical and musical teaching of high quality, studying harmony with Nadia Boulanger,counterpoint and fugue with Claude Delvincourt,musicology with Yvonne Rokseth who gave him insight into medieval music. At the Conservatoire de Paris, he followed Maurice Emmanuel's class of music history and studied music composition with Henri Büsser (himself a disciple of Charles Gounod). At the Sorbonne, he studied music history with André Pirro, with whom he presented his first musicological work in 1935 (DES, "Diplôme d'Études Supérieures"). He also took classes of conducting with Pierre Monteux, Willem Mengelberg and Bruno Walter in Amsterdam, while resident in the Descartes House (1935-1936). There, he also studied musicology with Albert Smijers.
Passionate about Medieval music for which he devoted much of his musicological activity, he founded in 1934 the choir Psalette Notre-Dame in order to revive it. In the same way, he founded at the Sorbonne under the direction of Gustave Cohen, the theater group the Théophiliens. Finally, he was actively involved in the founding of the Groupe de Théâtre antique de la Sorbonne (In particular with Jacques Veil and Roland Barthes). In this university, he completed his two theses on music, within the framework of the curriculum of Medieval French literature: L'École musicale de Saint-Martial de Limoges jusqu'à la fin du XIe as well as Chansons de Gautier du Coinci.