Franz-Valéry-Marie Cumont (3 January 1868 in Aalst, Belgium – 20 August 1947 in Woluwe-Saint-Pierre near Brussels) was a Belgian archaeologist and historian, a philologist and student of epigraphy, who brought these often isolated specialties to bear on the syncretic mystery religions of Late Antiquity, notably Mithraism.

After receiving royal travelling fellowships, he undertook archaeology in Pontus and Armenia (published in 1906) and in Syria, but he is best known for his studies on the impact of Eastern mystery religions, particularly Mithraism, on the Roman Empire.

There was a vigorous press campaign and student agitation in Cumont's favor, because the refusal was seen as blatant religious interference in the university's life.

When another candidate was named, in 1912, Cumont resigned his positions at the university and at the Royal Museum in Brussels, left Belgium and henceforth divided his time between Paris and Rome.

In 1997 the Royal Library, Brussels, observed the fiftieth anniversary of Cumont's death appropriately, with a colloquium on syncretism in the Mediterranean world of Antiquity.