Colossoemys is an extinct genus of alligatoroid crocodilian that inhabited South America during the Pleistocene epoch. The genus was originally named on the basis of two large procoelous vertebrae, a pubis, and a plastral fragment (likely to be from a turtle rather than a crocodilian). The paucity of material associated with the genus has led Colossoemys to be considered a possible nomen dubium in the past.