| Named By: | E. Buffetaut, V. Suteethorn, G. Cuny, H. Tong, J. Le Loeuff, S. Khansubha, & Jongautchariyakul in 2000 |
| Time Period: | Late Triassic 214-201 Ma |
| Location: | Thailand - Nam Phong Formation |
| Size: | Estimated to about 6.5 meters long |
| Diet: | Herbivore |
| Fossil(s): | Partial post cranial remains including vertebrae, partial ribs, left femur (thigh bone), right sternum and shoulder blade, possibly from a juvenile |
| Classification: | | Chordata | Reptilia | Dinosauria | Saurischia | Sauropodomorpha | Sauropoda | |
Isanosaurus (meaning "Isan [north-eastern Thailand] lizard") was one of the first sauropod dinosaurs. It lived approximately 210 million years ago during the Upper Triassic (late Norian to Rhaetian stages) in Thailand. The only species is Isanosaurus attavipachi. Though important for the understanding of sauropod origin and early evolution, Isanosaurus is poorly known. Exact relationships to other early sauropods remain unresolved.