The Hispaniolan giant tree frog or Hispaniola tree frog (Osteopilus vastus) is a species of frog in the family Hylidae endemic to Hispaniola and found in both the Dominican Republic and Haiti. It is patchily distributed in across the island. Populations from the southern part of Hispaniola may represent a separate, as yet undescribed species. These frogs are primarily found in mesic broadleaf forests but also in a range of agricultural habitats, such as cacao and coffee plantations and pastures. They can be found high in the canopy (up to 15 m). They are often found along creeks and streams; males call from trees overhanging running water. Eggs are also deposited in running water. This species is threatened by habitat loss caused by degradation of streams and deforestation.