Jean Victor Arthur Guillou (born April 18, 1930 in Angers) is a French composer, organist, pianist, and pedagogue.

Following autodidactic studies in piano and organ performance, Guillou became organist at the church St. Serge in Angers at the age of 12. He studied at the Paris Conservatoire under Marcel Dupré, Maurice Duruflé and Olivier Messiaen. In 1955, he accepted a position as professor of organ and composition at the Institute of Sacred Music in Lisbon. In 1958 and moved to Berlin, where he lived for the following five years. He eventually came back to Paris where he is Titular Organist at Saint Eustache church, since his appointment in 1963 when he succeeded to André Marchal.

He has a worldwide reputation as a brilliant concert organist and improviser. Additionally, he often performs as pianist; for example, he gave the English and French premieres of Julius Reubke's long-forgotten piano sonata in B-flat minor.

Guillou's engagement in organ building led to collaborations with several organ builders and the construction of new instruments in l'Alpe d'Huez, in the Chant d'Oiseau church in Brussels, in the Tonhalle[disambiguation needed] in Zurich, in the Conservatory in Naples, in the Auditorio de Tenerife and most recently (2008) in the San Antonio dei Portoghesi church in Rome.

As a composer, he has written more than 80 works - most of which being published by Schott - for organ, chamber and orchestral music, as well as numerous transcriptions for organ. In addition, Guillou has issued numerous organ recordings (Philips, Dorian, Festivo, Decca, Augure among others) including the complete organ works of Johann Sebastian Bach, César Franck, Robert Schumann, numerous historical improvisations (e.g., Visions Cosmiques (1969), or Jeux d'orgue (1970) re-edited in 2010 by Decca), as well as most of his own organ compositions on a series of 7 CDs (2010) for the Universal Philips label.

From 1970-2005, Guillou taught organ performance and improvisation at the annual Züricher Meisterkurse. Since 2007, these masterclasses are held at St. Eustache in Paris, France.