| Named By: | O. Alcobar & J. M. Parrish in 1997 |
| Time Period: | Late Triassic |
| Location: | Argentina, San Juan province - Ischigualasto Formation |
| Size: | About 3 meters long |
| Diet: | Carnivore |
| Fossil(s): | Partial remains |
| Classification: | | Chordata | Reptilia | Rauisuchia | Paracrocodylomorpha | Poposauroidea | Shuvosauridae | |
Sillosuchus is a genus of poposaurid crurotarsans from the Late Triassic of Argentina. It had an estimated length of about 3 m (10 ft).
The generic name refers to Dr. William Sill, and suchus, from the Greek word meaning "crocodile". A reconstruction of the fossil was presented in 2008 by the National University of San Juan in Argentina, in an homage to Dr. William Dudley Sill who was an important promotor of paleontology in San Juan.
Sillosuchus is the only poposaurid currently known from outside North America. Other members of the clade include Shuvosaurus, Poposaurus and Effigia.