The red-eyed tree frog is a slender, smooth skinned, medium-sized frog, up to about 2.5 inches in length. With its combination of red eyes, bright green dorsal color, and dark blue, purple or brownish flanks with cream-colored vertical bars, it can be mistaken for no other frog. The feet are generally orange in color, with the tips of the digits expanded to form discs. The fingers are about half-webbed, while the toes are about two-thirds webbed. Males are smaller than females. Their large eyes have vertical elliptical pupils.