This article traces music critic Émile Vuillermoz’s changing views on Igor Stravinsky. Vuillermoz, who kept company with Stravinsky in Paris starting in 1910, was initially a fervent supporter of the composer, until the early 1920s. He enthusiastically applauded Stravinsky’s early works, which he believed sought to provoke sensations rather than appeal to the listener’s reason. A letter sent by Stravinsky to Vuillermoz on June 28, 1912, which is now receiving musicological attention for the first time, is of particular interest since the composer indirectly endorses aesthetic principles that are the antithesis of those for which he would later advocate, especially with regard to the non-expressiveness of music. Stravinsky’s neoclassical turn influenced the younger generation of composers working in France, who saw it as a means of freeing themselves from Debussyism. Vuillermoz, ever a fervent champion of Debussyism, therefore gradually turned away from the Russian composer, but without ever denying his genius. Vuillermoz’s writings on Stravinsky became the site of debates that went beyond the mere evaluation of his works: the critic was defending his conception of music-sensation and fighting those who rejected the Debussyist and “impressionist” legacy. Vuillermoz would thus undertake to isolate the composer by presenting him as a maverick whose example should not be followed.