| Named By: | J. E. Powell in 1990 |
| Time Period: | Late Cretaceous, 95-90 Ma |
| Location: | Argentina, Chubut Province - Bajo Barreal Formation |
| Size: | Up to ten meters long |
| Diet: | Herbivore |
| Fossil(s): | Remains of three individuals, one of which is represented by an articulated and almost complete partial post cranial specimen |
| Classification: | | Chordata | Reptilia | Dinosauria | Saurischia | Sauropodomorpha | Sauropoda | Titanosauria | Lithostrotia | |
Epachthosaurus (meaning "heavy lizard") was a genus of dinosaur from the Late Cretaceous. It was a titanosaurid sauropod. Its fossils have been found in Central and Northern Patagonia in South America.