Sicyopterus aiensis, n. sp., a freshwater goby, is described on the basis of 30 specimens collected from streams of Vanuatu. It differs from other species belonging to the genus by a combination of characters including the number of pectoral rays, scales in the lateral series, predorsal scales, scales in a zigzag series on the caudal peduncle, number of soft rays in the second dorsal fin and live color.