We erect Mekongbathynella, new genus, to accommodate two new parabathynellid species, M. sesanensis and M. kryi, collected from subterranean water in Cambodia. The new genus is characterized by: the sexual dimorphism of the second antennular segment in the form of a 2-lobed projection in the male, the mandible with seta-like proximal teeth and a molar process having six dentate spines, including the most distal one being distally wide and bifurcated, the absence of a medial seta on the second maxillary segment, the male thoracopod VIII with massive protopod and basipod, rudimentary epipod, the exopod having dentate distal lobes and setae and endopod pointing backward, the absence of a pleopod and the uropod having two spines. The characters distinguishing the two new species are provided in a table. Mekongbathynella is closely related to Eobathynella yeojuensis Schminke, 2011, because of the similarities in the 6-segmented antennule and antenna, in the feature of the mouthparts and thoracopods I–VII, in the general shape of the male thoracopod VIII, and in the absence of pleopod I. In the context of the affinity, the details of the male thoracopods of the two new species and E. yeojuensis are compared. The status of Eobathynella is briefly discussed.