Nebalia kocatasi sp. nov. (Crustacea: Leptostraca) is described from specimens collected off the coast of Turkey (Aegean Sea). The new species differs from the other known species of the genus in having a rostrum about 2.4 times as long as wide, the antennular scale is twice as long as wide, the third article of the antennule has up to four short distal spines, the third article of the antenna has three robust spines on the external lateral face, the two distalmost being the longest, the endopod of the second maxila is composed of two sub-equal articles, the exopod of the second maxilla is as long as the first article of the endopod, pleonites 6–7 have pointed denticles along the posterior dorsal borders, the protopod of pleopod 4 has 2–3 serrations along the posterior border and the terminal seta of the caudal furca is about twice the length of rami. This is the second leptostracan species reported to date from the eastern Mediterranean.