Valdosaurus ("Weald Lizard") is a genus of bipedal herbivorous iguanodont ornithopod dinosaur found on the Isle of Wight and elsewhere in England, Spain and possibly also Romania.

In the nineteenth century Reverend William Darwin Fox collected two small thighbones near Cowleaze Chine on the southwest coast of the Isle of Wight.

The specific name means "with a small channel" in Latin, referring to a distinct groove between the condyles of the lower thighbone.

[2] A second species, V. nigeriensis, was described by Galton and Philippe Taquet from younger rocks from Niger in 1982;[3] this has since been transferred to its own genus, Elrhazosaurus.

[9] Having a close European relative of the American form Dryosaurus named led to most of the dryosaurid fossil material of Europe being referred to Valdosaurus.

Valdosaurus was seen as not only present in England (the Wessex Formation of the Isle of Wight and the Hastings Beds of West Sussex) but probably also in Spain[citation needed].