| Named By: | A. Yu. Berezin in 2011 |
| Time Period: | Early Cretaceous, 133-130 Ma |
| Location: | Russia, Chuvashia/Chuvash Republic |
| Size: | Unavailable |
| Diet: | Piscivore |
| Fossil(s): | Partial post cranial remains |
| Classification: | | Choradata | Reptilia | Sauropterygia | Plesiosauria | Cryptoclididae | |
Abyssosaurus is an extinct genus of cryptoclidid plesiosaur known from the Early Cretaceous of Chuvash Republic, western Russia.