A new species of Galumnidae, Dimidiogalumna grandjeani sp. nov., is described from bird's nest (Black-and-red Broadbill, Cymbirhynchus macrorhynchos) in southern Vietnam. It is the first member of this genus recorded from the Oriental Region. The new species is most similar to D. comoroensis Mahunka, 1994 in having the elongate notogastral porose areas Aa, however, it differs from the latter by the presence of four pairs of notogastral porose areas and the absence of anterior notogastral margin and ridges on anal plates. An identification key to the known species of Dimidiogalumna is given.