François Gagnepain was a French botanist. The standard botanical author abbreviation Gagnep. is applied to plants described by Gagnepain.
With Achille Eugène Finet, he named a number of species within the botanical family Annonaceae. The genus Gagnepainia was named in his honor by Karl Moritz Schumann. The French Academy of Sciences awarded Gagnepain the Prix de Coincy for the year 1907.