In 2001 and 2002, a study of many-lined skinks (Plestiodon multivirgatus) was conducted by Los Alamos National Laboratory biologists in north-central New Mexico to determine means and ranges for several morphological characters and to test for sexual dimorphism. Over both years, there were 539 new captures of many-lined skinks, which included 131 Hatchlings. The earliest hatchling capture was on 19 June and the latest capture was on 31 August. Hatchling captures peaked on 1 August in 2001 and 6 August in 2002. The age class, sex, snout—vent length (SVL), tail length (TL), mass, head length (HL), and head width (HW) were recorded and individuals were released at the point of capture. Our results indicate that the SVL, mass, HL, and HW did not exhibit sexual dimorphism. The sex ratio was skewed toward females in this study. It is not known whether the many-lined skink has sexual determination based on environmental factors, but the data here suggest that more research is needed. From these observations, we supplement the limited existing knowledge on the morphology of this species.