Koponenius, the westernmost genus of the basically Australasian family Haplodesmidae which has hitherto been known by two species only, one each from Nepal and northern India, is recorded in Myanmar for the first time. It is represented there by K. simplex n. sp., from Chin State, the first haplodesmid to be described from Myanmar. This new species nicely fills in the considerable gap in the distribution of indigenous Haplodesmidae lying between the Himalayas, on the one hand, and Thailand and Yunnan Province, southern China, on the other hand.