Lophiodon (from lóphos, 'crest' and odoús 'tooth') is an extinct genus of mammal related to chalicotheres. It lived in Eocene Europe, and was previously thought to be closely related to Hyrachyus. Lophiodon was named and described by Cuvier (1822) based on specimens from the Sables du Castrais Formation. There are various species of Lophiodon known to have existed throughout Eocene Europe, where they were the largest herbivorous mammals in the region.