(Uploaded by Plazi for the Bat Literature Project) To date, 110 bat species are recorded in Peninsular Malaysia. Many of these species depend upon tropical forests, which have rapidly decreased in extent over recent decades. Yet, updated information on species distributions in the region is still lacking. Here, we report bat species records and their distribution based from surveys undertaken at 30 lowland tropical rainforest sites across Peninsular Malaysia. We recorded 56 species from seven families. The three most abundant species across the peninsula were Rhinolophus affinis, Hipposideros bicolor complex and Hipposideros cervinus. Four out of nine singleton species (Chironax melanocephalus, Coelops robinsoni, Myotis hermani and Hesperoptenus doriae) are forest specialists that are patchily distributed across the peninsula, while another five are open space/edge species that utilise the forest occasionally. The understorey assemblage comprises frugivorous, insectivorous and nectar-drinking species. Thirteen percent of all captured species are represented by at least one record outside of their previous known distributional range. Furthermore, our study suggests that updated and informative species distribution is essential to further study these bat species since information on their ecology and basic natural history remains poorly known. An improved understanding of species ecology and population status will contribute to more effective conservation efforts. Our survey data provide comprehensive records of understorey forest bats in a biodiversity hotspot.