| Named By: | Robert Broom in 1911 |
| Time Period: | Early Jurassic |
| Location: | South Africa |
| Size: | Uncertain due to lack of fossil remains |
| Diet: | Herbivore |
| Fossil(s): | Jaw bone and fragmentary limb bones |
| Classification: | | Chordata | Reptilia | Dinosauria | Ornithischia | Ornithopoda | |
Geranosaurus (meaning "sloth reptile") is a genus of ornithischian dinosaur from the Early Jurassic. It is known only from a jaw bone and limb elements discovered in South Africa. Because of the limited remains, it is considered a nomen dubium. It is classified as an ornithischian based on the jaw, probably a heterodontosaurid.
The type species, Geranosaurus atavus, was described by Robert Broom in 1911. The genus name is derived from Greek geranos, "sloth", a reference to the sloth-like hind-limb. The specific name means "ancestor" in Latin. The limb elements have inventory number SAM 1871.