Dimorphodon (pronounced: die-MORF-oh-don) meaning (Two-form Teeth) was a species of medium-sized pterosaur from the premature Jurassic Period. It belonged to the Order Pterosauria, Suborder Rhamphorhynchoidae and belonged to the relatives Dimorphodontidae.

It was named by paleontologist Richard Owen in 1859. Dimorphodon means two-form fang referring to the fact that it had two dissimilar types of teeth in its jaws - which is relatively rare among reptiles. Fossil ruins have been found in England. Mary Anning (1799 - 1847) was famous for her Dimorphodon discovery at Lyme Regis in Dorset, UK. This region of Britain is now a World Heritage Site, dubbed the Jurassic Coast. Dimorphodon was roughly 1 metre (3.3 ft) long, with a 1.2 metres (4 ft) wingspan.

It has been argued that Dimorphodon was a biped, though fossilised track ruins of other pterosaurs (ichnites) illustrate a quadrupedal gait while on the ground. Its teeth and jaws recommend it was, like most pterosaurs, a piscivore (fish eater). Most depictions show a puffin-like beak.

Unlike the majority other pterosaurs, Dimorphodon's legs sprawled out at the sides. making its walking gait inept. This might indicate that Dimorphodon spent much of its non-flying time lynching from cliffs or tree branches, holding on with its toe claws.

Dimorphodon lived roughly 200 million to 180 million years ago.