Huallasaurus (meaning "duck lizard") is an extinct genus of saurolophine hadrosaur from the Late Cretaceous Los Alamitos Formation of Patagonia in Argentina.

Originally named as a species of Kritosaurus in 1984,[1] it was long considered a synonym of Secernosaurus[2] before being recognized as its own distinct genus in a 2022 study, different from other members of Kritosaurini.

[3] The generic name, "Huallasaurus," combines "hualla," the Mapudungun word for "duck," and the Greek "sauros," meaning "lizard."

[3][1] Rozadilla et al. (2022) named Huallasaurus and the closely related Kelumapusaura, recovering them in a clade of entirely South American saurolophines.

They named the clade containing Huallasaurus, Kelumapusaura, and other South American saurolophines as the Austrokritosauria, recovering it as the sister taxon to the Kritosaurini.