Yubaatar is a genus of multituberculate, an extinct order of rodent-like mammals, which lived in what is now China during the Late Cretaceous.

The first specimen was discovered in the Qiupa Formation of Luanchuan County, in the Henan Province.

The specimen consists of a partial skeleton with a nearly complete skull, and was made the holotype of the new genus and species Yubaartar zhongyuanensis by the Chinese palaeontologist Li Xu and colleagues in 2015.

The holotype specimen had a palaeopathology unique among known Mesozoic mammal, a severely broken right tibia bone, which was probably damaged in an accident, but had healed.

The morphology of Yubaatar indicates that diversity in the complexity of the teeth of multituberculates, relating to their diets, increased with the number of genera and difference in body size, and that there was a shift in adaptations towards increased herbivory in the group across the Cretaceous–Paleogene boundary.