Barilium is a genus of iguanodontian dinosaur which was first described as a species of Iguanodon (I. dawsoni) by Richard Lydekker in 1888, the specific epithet honouring the discoverer Charles Dawson. A contemporary of Hypselospinus (also once thought to be a species of Iguanodon), Barilium was a robust iguanodontian estimated at 8 metres (26 feet) long.