Leiognathus longispinis (Valenciennes, in Cuvier and Valenciennes, 1835) is shown to be a senior synonym of Leiognathus smithursti (Ramsay and Ogilby, 1886). Many leiognathid species were described without a broad comparison to existing species, which has contributed to nomenclatural problems. Although the holotypes of both L. longispinis and L. smithursti were collected in New Guinea, the authors of the latter name were evidently unaware of the earlier named species, which is shown herein to be morphologically indistinct from L. smithursti.