Estesia (in honour of Richard Estes) is an extinct genus of Late Cretaceous anguimorph lizard found in the Gobi Desert in Mongolia.

It was discovered in June 1990 by a joint expedition made up of Mongolian and American palaeontologists, and described in 1992 by Mark Norell, Malcolm McKenna and Michael Novacek.

This animal is of interest to palaeontologists, not only because it is close to the lineage of modern Gila monsters (Heloderma), but also because its dentition shows evidence that it was venomous.

In the description, Estesia was assigned to Varanoidea, as the sister group to Varanidae, based on skull characters.

The phylogenetic analysis presented by Norell and Gao (1997) actually supported the creation of a new group that included modern Gila monsters and extinct pre-historic forms, the Monstersauria.