Symmetrodonta is a group of Mesozoic mammals and mammal-like synapsids characterized by the triangular aspect of the molars when viewed from above, and the absence of a well-developed talonid.

The traditional group of 'symmetrodonts' ranges in age from the latest Triassic to the Late Cretaceous, but most research in the last 20-30 years has concluded that they are not a true taxonomic group, but include several unrelated branches of the mammal tree.

Particular sub−groups of Symmetrodonta are better studied, e.g. Spalacotheriidae, which has acute−angled molariform teeth, strongly reduced talonids, and conspicuous anterior and posterior cingulids.

Though some forms like Zhangheotherium retain a Meckelian groove, at least Spalacotheriinae lost it, acquiring modern ear anatomy.

[7] It shows evidence of tarsal spurs, indicating that, like most non-therian Mammaliaformes, at least some symmetrodonts were venomous like the modern platypus.