Stegomosuchus is an extinct genus of small protosuchian crocodylomorph. It is known from a single incomplete specimen discovered in the late 19th century in Lower Jurassic rocks of south-central Massachusetts, United States. It was originally thought to be a species of Stegomus, an aetosaur (a type of armored herbivorous reptile), but was eventually shown to be related to Protosuchus and thus closer to the ancestry of crocodilians.