Zephyrosaurus (ZEF-eye-roh-SAWR-us) was an ornithopod dinosaur. Its fossils were found in strata dating to the early Cretaceous. The type species, Zephyrosaurus schaffi was described by Sues in 1980. The fossils include one partial skeleton, found in Montana, United States.

Zephyrosaurus was a plant-eating dinosaur 6 feet (1.8 meters) long. It had a small head, flat cheek teeth, long legs, and short arms. It was an ornithopod and a hypsilophoditid in the Aptian-Albian ages, about 119-113 million years ago. It was found in Montana, USA and was named by paleontologist H.D. Sues in 1980. It is known from a partial skull and some vertebrae.