Arginbaatar is a genus of extinct mammal from the Lower Cretaceous of Mongolia.

The primary species, Arginbaatar dmitrievae, was also named by Trofimov.

The fossil remains date to the Aptian or Albian (Lower Cretaceous) Dzunbain Formation of Mongolia.

Some characteristics are "Plagiaulacida"-like, while others are more akin to the further derived suborder of Cimolodonta.

"This family shows a mixture of 'plagiaulacidan' and cimolodontan characters" (Kielan-Jaworowska & Hurum, 2001, p. 415).