New data are presented for the potter wasp genus Orancistrocerus van der Vecht ( Eumeninae , Odynerini ) occurring in Vietnam. Two species are described as new to science: Orancistrocerus thanhnhat sp. nov. and O. thanghen sp. nov. Orancistrocerus aterrimus erythropus van der Vecht is synonymized with Orancistrocerus aterrimus aterrimus (de Saussure); the male genitalia of this species are described for the first time. An updated key is presented to all species of the genus.