Léon Nicolas Marie Joseph Halkin (1872–1955) was a Belgian historian and classicist who spent much of his life as a professor at the University of Liège.
He studied Greek and Latin at the Athénée royal de Liège, and graduated from the University of Liège on 24 July 1894 with a doctorate in classical philology.
In 1895, he won a travel bursary, with which he studied at the Collège de France and the École pratique des hautes études in Paris, following courses by Antoine Héron de Villefosse, René Cagnat and Louis Havet.
[2] Halkin briefly taught at the Athénée royal de Mons (1896) and the École des Cadets in Namur (1897) and, on 20 February 1900, he was appointed to the University of Liège, where he remained for the next forty-three years.
[3] He was married to Elvire Courtoy (1873–1947), with whom he had five children, including Léon-Ernest Halkin, professor of history at the University of Liège, and the Bollandist François Halkin.