Bonatitan is a genus of titanosaurian dinosaur from Argentina. It lived during the Late Cretaceous. The type species is Bonatitan reigi, first described by Martinelli and Forasiepi in 2004. The specific epithet honours Osvaldo Reig. The description is based on a partial skeleton, including a braincase and caudal vertebrae. It was named after the famous Argentine paleontologist José Fernando Bonaparte.