| Named By: | Fidel Torcida FernandezinBaldor, Jose Ignacio Canudo, Pedro Huerta, Diego Montero, Xabier Pereda Suberbiola & Leonardo Salgado in 2011 |
| Time Period: | Early Cretaceous, 125 Ma |
| Location: | Spain, Burgos Province - Castrillo la Reina Formation |
| Size: | Uncertain, but estimated at somewhere between 10 and 12 meters long |
| Diet: | Herbivore |
| Fossil(s): | Partial cranial and post cranial skeletal remains |
| Classification: | | Chordata | Reptilia | Dinosauria | Saurischia | Sauropodomorpha | Sauropoda | Diplodocoidea | Rebbachisauridae | |
Demandasaurus (meaning "Demanda lizard") is a genus of rebbachisaurid sauropod dinosaur from early Cretaceous (late Barremian - early Aptian stage) deposits of Spain. Demandasaurus is known from an incomplete but associated skeleton that includes cranial and postcranial remains. It was collected from the Castrillo la Reina Formation in Burgos Province of Spain. It was first named by Fidel Torcida Fernandez-Baldor, Jose Ignacio Canudo, Pedro Huerta, Diego Montero, Xabier Pereda Suberbiola and Leonardo Salgado in 2011 and the type species is Demandasaurus darwini.