Jeanne Marie-Madeleine Demessieux (14 February 1921 – 11 November 1968) was a French organist, pianist, composer, and teacher.

After taking private piano lessons with her elder sister, Yolande, Jeanne entered the Montpellier Conservatoire in 1928.

In 1933, she began her studies at the Paris Conservatoire; studying piano with Simon Riera and Magda Tagliaferro, harmony with Jean Gallon, counterpoint and fugue with Noël Gallon, and composition with Henri Büsser.

This was the beginning of her career as an international concert organist and improviser, but also coinciding with Dupré irrevocably turning his back on Demessieux.

According to her biographer, Christiane Trieu-Colleney, Demessieux underwent medical treatment and did not perform in concert for most of the last year of her life.