The Sundaic Mountain Leopoldamys is a large rat recorded in montane forests of the Malay Peninsula and Sumatra. It has a long tail and a dark-to-pale coat pattern.
The back is dark brown to gray, the flanks fawn, and the belly sharply paler, yellowish white. It has a long tail and long whiskers.
It is terrestrial and uses crevices among roots and rocks on mossy forest floors. Records also mention low branches and tree holes.
An extinction-risk assessment has not been added yet.