Molecular data from samples encompassing 22 nominal species of Poropuntius indicate that the species-level diversity in the genus has been vastly overestimated, likely due to inadequate taxon and geographic sampling and reliance on morphological characters that vary intra-specifically. The latter includes discrete mouth morphologies related to alternate feeding strategies (ecomorphs) within populations. One new species is described, Poropuntius anlaoensis Hoàng, Phạm & Trần, sp. nov., and 17 synonyms of six valid species names of Poropuntius, P. krempfi, P. alloiopleurus, P. huangchuchieni, P. laoensis, P. kontumensis, and P. deauratus, are recognised. Additional taxonomic changes in this widespread and generally poorly known genus are likely as more molecular and morphological data become available.