Two new genera and species of Tritylodontidae, Shartegodon altai and Nuurtherium baruunensis, are described and compared with other known tritylodontids. The new taxa are represented by two partial skulls and, in the case of Nuurtherium, postcranial elements. They were collected from the lower part of the Ulan Malgait Sequence (Upper Jurassic) in the Shar Teg locality, Gobi-Altai Aimag, southwestern Mongolia. The upper postcanine teeth of these two genera have unique cusp formulae that differentiate them from other tritylodontids. As has been suggested for most tritylodontids in general, these two new genera may have been herbivorous.