Romeosaurus is an extinct genus of yaguarasaurine mosasaur known from the early Late Cretaceous "Lastame" lithotype of northern Italy. It contains two species, Romeosaurus sorbinii and Romeosaurus fumanensis. Of the 2 species, R. sorbinii is known only through very fragmented fossil records of a single specimen and is otherwise poorly described. R. fumanensis is known through more specimens found across a small geographic area in Italy.