| Named By: | Kuhn in 1964 |
| Time Period: | Early Triassic, 247.5-247.2 Ma |
| Location: | Germany, Lower Saxony |
| Size: | Uncertain due to incomplete remains. but sail is roughly 1.4 meters long |
| Diet: | Uncertain, but presumed carnivore |
| Fossil(s): | Dorsal and caudal vertebrae, ribs and shoulder girdle preserved on two slabs |
| Classification: | | Chordata | Reptilia | Archosauria | Crurotarsi | Rauisuchia | Paracrocodylomorpha | Poposauroidea | Ctenosauriscidae | |
| Also known as: | | Ctenosaurus koenei | |
Ctenosauriscus is an extinct genus of sail-backed poposauroid archosaur from Early Triassic deposits of Lower Saxony in northern Germany. It gives its name to the family Ctenosauriscidae, which includes other sail-backed poposauroids such as Arizonasaurus. Fossils have been found in latest Olenekian deposits around 247.5-247.2 million years old, making it one of the first known archosaurs.