Protohadros (meaning "first hadrosaur") is a genus of herbivorous ornithischian dinosaur from the Late Cretaceous (Cenomanian stage).

Gary Byrd, a part-time palaeontologist, discovered some remains of this euornithopod (ribs and an ungual) during early 1994 at Flower Mound, Denton County, north-central Texas.

He informed professional palaeontologist Yuong-Nam Lee of the find, who arranged for the entire preserved fossil to be excavated.

The genus name is derived from Greek πρῶτος, protos, "first", en ἁδρός, hadros, "thick", a reference to the fact that Head considered the species the oldest known hadrosaur.

[2] The holotype, specimen SMU 74582, of Protohadros, was found in the Woodbine Formation, which dates to the middle Cenomanian.