| Named By: | John Willis Stovall & Wann Langston, Jr. in 1950 |
| Time Period: | Early Cretaceous Aptian to Albian, 116-110 Ma |
| Location: | USA, Oklahoma, Antlers Formation, and the Texas, Twin Mountains Formation. Some specimens from other parts of the US |
| Size: | Up to 11.5 meters long |
| Diet: | unavailable |
| Fossil(s): | Several specimens of partial remains. Combined study of all these specimens has allowed Acrocanthosaurus to be very well reconstructed |
| Classification: | | Chordata | Reptilia | Dinosauria | Saurischia | Theropoda | Carcharodontosauridae | |
Acrocanthosaurus ( ak-ro-KAN-tha-SAWR-as; meaning "high-spined lizard") is a genus of theropod dinosaur that existed in what is now North America during the Aptian and early Albian stages of the Early Cretaceous. Like most dinosaur genera, Acrocanthosaurus contains only a single species, A. atokensis. Its fossil remains are found mainly in the U.S. states of Oklahoma, Texas, and Wyoming, although teeth attributed to Acrocanthosaurus have been found as far east as Maryland.
Acrocanthosaurus was a bipedal predator. As the name suggests, it is best known for the high neural spines on many of its vertebrae, which most likely supported a ridge of muscle over the animal's neck, back and hips. Acrocanthosaurus was one of the largest theropods, reaching 11.5 m (38 ft) in length, and weighing up to 6.2 tonnes (6.8 short tons). Large theropod footprints discovered in Texas may have been made by Acrocanthosaurus, although there is no direct association with skeletal remains.
Recent discoveries have elucidated many details of its anatomy, allowing for specialized studies focusing on its brain structure and forelimb function. Acrocanthosaurus was the largest theropod in its ecosystem and likely an apex predator which preyed on sauropods, ornithopods, and ankylosaurs.