Zoeal stages of Conchodytes nipponensis, not previously known from Korea, are described from laboratory-reared material. This is the first account of the larval development of a species from the genus Conchodytes and the first larval description of a pontoniid species from Asian waters. The Gnathophyllidae had been considered as a synonym with the Pontoniinae by Bruce, whereas others regard both groups as distinct. Morphological comparisons between the first zoea of C. nipponensis and that of Gnathophyllum americanum indicate that the Gnathophyllidae have great affinity with the Pontoniinae. According to the viewpoint of some authors, similar larvae do not necessarily signify related adults. Therefore, the Pontoniinae and the Gnathophyllidae may be distinct.