The glochidial shell morphology of Solenaia khwaenoiensis from Khwaenoi River, Phitsanulok, Thailand, was studied. Electron micrographs of unique characteristics are described. Solenaia khwaenoiensis shells are classified in the second group, which is unequivalve, unequilateral. However, the external and internal shell surfaces have unique porous structures. A hook-like shell appendix structure was also observed.