A fragmentary braincase from the Baynshirenskaya Svita (Cenomanian–Turonian) of Amtgay, Omnogov, People’s Republic of Mongolia was described as the holotype specimen of the ankylosaurid dinosaur, Amtosaurus magnusKurzanov and Tumanova 1978. However, the validity of this genus has been questioned by several authors. Recently, a second species, based on a fragmentary specimen consisting of a braincase and partial skull roof, was assigned to Amtosaurus as A. archibaldiAverianov 2002. Here we re-assess the status of Amtosaurus and of the referred species, A. archibaldi. We conclude that “Amtosaurus magnus” is a nomen dubium that should be regarded as Ornithischia indeterminate. However, “A.” archibaldi is a valid taxon, characterized by an autapomorphic feature of the skull roof, and we refer this species to the new genus Bissektipelta.