The previously unreported tadpole of Leptopelis karissimbensis, an endangered treefrog from Rwanda, is described. Tadpoles were collected, photographed, measured, and examined for standard metrics of tadpole morphology. Larvae of L. karissimbensis resemble other tadpoles in the genus Leptopelis in being muscular, elongate, and eel-like. The lateral tooth row formula for L. karissimbensis is 4/3. In late stage larvae, tadpoles of L. karissimbensis exhibit a prominent white spot below the eye. Larvae of this species were often abundant in suitable habitat at approximately 2,800 m in elevation. Larval habitat for L. karissimbensis includes seasonally flooded marshes, forest pools, and permanent ponds in the Virunga Mountains, the only known range of this species.