Paul Marie Théodore Vincent d'Indy (French: [vɛ̃sɑ̃ dɛ̃di]; 27 March 1851 – 2 December 1931) was a French composer and teacher. His influence as a teacher, in particular, was considerable. He was a co-founder of the Schola Cantorum de Paris and also taught at the Paris Conservatoire. His students included Albéric Magnard, Albert Roussel, Arthur Honegger, Darius Milhaud, Yvonne Rokseth, and Erik Satie, as well as Cole Porter.

D'Indy studied under composer César Franck, and was strongly influenced by Franck's admiration for German music. At a time when nationalist feelings were high in both countries (circa the Franco-Prussian War of 1871), this brought Franck into conflict with other musicians who wished to separate French music from German influence.