François-Xavier Dillmann (born 27 November 1949) is a French philologist who specializes in Old Norse studies.
Dillmann studied at the universities of Lille, Uppsala, Copenhagen, Iceland, Göttingen, Munich and Caen.
Since 1988, Dillmann has been Chair of the History and Philology of Ancient and Medieval Scandinavia at 4th Section (History and Philology) at the École pratique des hautes études.
He is the founder and President of the Société des études nordiques, and editor of its journal Proxima Thulé [fr].
Dillmann was written a number of works on Viking Age history and culture, Old Norse religion and literature, and runes.