Tatisaurus is a genus of ornithischian dinosaur from the Early Jurassic from the Lower Lufeng Formation in Yunnan Province in China.

[2] The holotype, FMNH CUP 2088, was found in the Zhangjiawa Beds of the Lufeng Formation, dating from the Sinemurian.

The lower jaw bone fragment is, lacking the tip, six centimetres long.

They instead found Tatisaurus to be a dubious basal thyreophoran, showing a single thyreophorean synapomorphy; a ventrally deflected mesial end of the dentary.

[5] In 2019 a study concluded that Bienosaurus was a nomen dubium, possibly identical to Tatisaurus from the same formation.