| Named By: | Charles Gilmore in 1933 |
| Time Period: | Late Cretaceous, 83-74 Ma |
| Location: | Mongolia - Iren Dabasu Formation |
| Size: | Approximately 5 meters long |
| Diet: | unavailable |
| Fossil(s): | Initially only a hind limb, skull and shoulder remains were later attributed to it on the grounds that further hind limb material matched the holotype. Further post cranial remains from China and Uzbekistan have been reported |
| Classification: | | Chordata | Reptilia | Dinosauria | Saurischia | Theropoda | Tyrannosauroidea | |
Alectrosaurus (meaning "alone lizard") is an extinct genus of tyrannosaurid theropod dinosaur that lived approximately 83 to 74 million years ago during the latter part of the Cretaceous Period in what is now Inner Mongolia. It was a medium-sized, moderately-built, ground-dwelling, bipedal carnivore, with a body shape similar to its much larger relative, Tyrannosaurus rex, and could grow up to an estimated 5 m (16.4 ft) long.