Abstract
A population of the triploid gecko, Hemidactylus stejnegeri Ota & Hikida 1989, was found on an off-shore island of Vietnam for the first time. Chromosomal analyses and multivariate analyses of meristic and morphometric characters revealed that Vietnamese populations are slightly but significantly differentiated from the Philippine and Taiwanese populations. The latter two, on the other hand, are poorly differentiated from each other morphologically. Male phenotypes were found in Vietnamese and Taiwanese populations, and their significance is discussed.