Abydosaurus (meaning "Abydos lizard") is a genus of brachiosaurid sauropod dinosaur known from skull and postcranial material found in upper Lower Cretaceous rocks of northeastern Utah, United States.

[1] Abydosaurus is based on the holotype DINO 16488, a nearly complete skull and lower jaws with the first four neck vertebrae.

These fossils were found in a sandstone bed at the base of the Mussentuchit Member of the Cedar Mountain Formation, near the old visitor center of Dinosaur National Monument.

The genus name is a reference to Egyptian mythology: Abydos is the Greek name for a city on the Nile where the head and neck of Osiris were buried, while the holotype of Abydosaurus consists of a head and neck found in rocks overlooking the Green River.

The type species is A. mcintoshi in honor of John S. ("Jack") McIntosh,[1] Professor of Physics, Emeritus, Wesleyan University, and his contributions to Dinosaur National Monument and the study of sauropod dinosaurs.