Leptomantis gadingensis is a small to mid-size tree frog. It was first described from Gunung Gading, western Sarawak (Das and Haas, 2005). 

The snout is obtuse and projects slightly beyond the mandible. The head is broader than it is long. Both the fingers and toes are webbed. Males lack nuptial pads, and there is no dermal flap along the forearm. A weak supracloacal fold is present, as well as a spinose calcar. The skin of the head is not co-ossified with the skull. The supratympanic fold is weak. The upper side is brown, marked with a dark interorbital bar, and decorated with dark brown or green blotches. Typically the dark blotches on the back are light edged. The groin are is white with dark blotches. The iris is usually coppery red around the pupil and yellowish bronze peripherally. 

Little is know about the ecology of this species. It seems to prefer primary or good secondary dipterocarp lowland forest. L. gadingensis produces small foam nests 2–5 m high in vegetation and overhanging streams. 

Tadpoles are stream adapted (rheophilous). Their oral disc is oriented towards the substratum and is cup-shaped. The tadpoles use their mouth to cling to rocks on pebble in moderate current.

Leptomantis gauni, L. gadingensis, L. belalongensis, and L. malkmusi are relatively similar morphologically in general appearance. Their intra- and interspecific variability and distributional ranges are not well understood. More genetic investigations are needed to fill the gaps of knowledge.