Acrocanthosaurus( meaning 'high-spined lizard') is a genus of theropod dinosaur that existed in what is now North America during the mid-Cretaceous Period, approximately 125 to 100 million years ago.

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, approaching 12 meters (40 ft) in length, and weighing up to about 2.40 metric tons (2.65 short tons).