The genus Microhyla contains dozens of species in Asia with a rich representation on Borneo. The species are minute to small, mostly terrestrial, and can locally be very abundant. The distribution covers major parts of Asia from India to China, and the Malay Peninsula to Bali.

The genus Nanohyla has recently been established for a group of almost a dozen Southeast Asian species of Narrow-mouthed Frogs formerly included in the genus Microhyla, some of them particularly small in body size. The new genus was justified with molecular and morphological data. The group contains two Bornean species: Nanohyla petrigena and Nanohyla perparva. This new taxonomy, however, has been challenged by Mahony et al (2024) who rather advocated to group these taxa as subgenus under Microhyla. Currently, we treat the two Bornean species under the genus Microhyla.