| Named By: | Edward Drinker Cope in 1868 |
| Time Period: | Late Cretaceous |
| Location: | North America |
| Size: | Average between 2 and 4 meters long. Largest known specimen is up to 6.2 meters long |
| Diet: | Piscivore/Carnivore |
| Fossil(s): | Several specimens |
| Classification: | | Chordata | Reptilia | Squamata | Mosasauridae | Mosasaurinae | Mosasaurini | |
Clidastes is a genus of extinct mosasaurine lizard that lived during the Late Cretaceous Period from 99.6 million to 66 million years ago in North America, and Europe. Clidastes was an agile swimmer that probably swam by undulating its body, and preyed on cephalopods, fish and other small vertebrates in shallow water.