Ernest Langlois (Heippes, 4 September 1857 – Lille, 15 July 1924) was a French medievalist, professor at the University of Lille.He is best known for his 1910 work Les manuscrits du Roman de la Rose, description et classement, on the manuscripts of the Roman de la Rose and subsequent five-volume edition Le Roman de la Rose par Guillaume de Loris et Jean de Meun.