| Named By: | Kenneth Carpenter in 1999 |
| Time Period: | Early Cretaceous, Aptian |
| Location: | Columbia - Paja Formation |
| Size: | Body up to 8 meters long, Skull 35 centimetres long |
| Diet: | Piscivore |
| Fossil(s): | Known from a skull and partial post cranial remains. Remains for up to two individuals so far known |
| Classification: | | Chordata | Reptilia | Sauropterygia | Plesiosauria | Elasmosauridae | |
| Also known as: | | Alzadasaurus colombiensis | Callawayosaurus | |
Callawayasaurus is a genus of plesiosaur from the family Elasmosauridae. When the first Callawayasaurus fossil was first discovered by Samuel Paul Welles in 1962, it was described as Alzadasaurus colombiensis before being moved into its current genus by Kenneth Carpenter in 1999.