| Named By: | Sander et al. in 1997 |
| Time Period: | Middle Triassic |
| Location: | USA, Nevada, Augusta Mountains - Favret Formation |
| Size: | Unavailable |
| Diet: | Piscivore |
| Fossil(s): | Skull and post cranial remains |
| Classification: | | Chordata | Reptilia | Sauropterygia | Pistosauroidea | |
Augustasaurus is a genus of aquatic sauropterygian reptile belonging to the Pistosauria, a clade containing plesiosaurs and their close relatives. Pistosaurus and Augustasaurus were thought to be the only known members of the family Pistosauridae. However, some recent cladistic analyses found Augustasaurus to be a more advanced pistosaur, as a sister group of the order Plesiosauria. The only known species of Augustasaurus is Augustasaurus hagdorni , which was first described in 1997.