Male Leptolalax heteropus grow to snout-vent length of 24–29 mm (0.94–1.14 in) and females to 32–36 mm (1.3–1.4 in). These frogs are usually encountered while perched on the leaves of small plants close the ground.[3] The call of male L. heteropus is short and consists of a short series of 3–6 notes, the first note being longer in duration and higher in dominant frequency than subsequent ones.[4] The call characteristics are among the features that separate this species from superficially similar Leptolalax solus. Indeed, frogs reported from Thailand as Leptolalax heteropus might actually be the relatively recently (2006) described L. solus.[5]