Thalassodraco is an extinct genus of ophthalmosaurid ichthyosaur from the Late Jurassic (Tithonian) Kimmeridge Clay Formation of England. The type species, T. etchesi, was named in 2020, with the epithet in honour of the discoverer of the holotype, Steve Etches.

The Kimmeridge Clay is a sedimentary deposit of fossiliferous marine clay which is of Late Jurassic to lowermost Cretaceous age and occurs in southern and eastern England and in the North Sea. This rock formation is the major source rock for North Sea oil. The fossil fauna of the Kimmeridge Clay includes turtles, crocodiles, sauropods, plesiosaurs, pliosaurs and ichthyosaurs, as well as a number of invertebrate species.