Anatomy: Hypsilophodon was about 6.5 feet long (2 m) and 2 feet (0.6 m) tall, weighing about 150 pounds (68 kg). Hypsilophodon had a beak made of horn, cheek pouches, and 28-30 self-sharpening cheek teeth in a small skull 4 3/4 inches (12 cm) long, by 2 inches (5 cm) wide. This ornithopod dinosaur may have had 2 rows of bony plates running down its back.

Fossils: About 20 Hypsilophodon fossils were found together on the Isle of Wight (off the southern coast of England). This shows that Hypsilophodon may have traveled in herds. Other Hypsilophodon fossils have been found in Spain.