We investigated life history traits (body sizes, sexual maturity, sexual dimorphism, clutch size) and dietary preferences in the sympatric lizards, Oligosoma nigriplantare polychroma and Oligosoma lineoocellatum (Scincidae). One-hundred and forty O. n. polychroma and 153 O. lineoocellatum were collected for a twelve month period. Our results show that these sympatric species have different life history traits, notably in body size, size at maturity, and reproductive output. O. n. polychroma were smaller (51.72 mm adult males, 56.74 mm adult females) than O. lineoocellatum (70.70 mm adult males, 76.30 mm adult females). Size at maturity was determined by logistic regression models of snout-vent length (SVL) for both species. O. n. polychroma reached sexual maturity at a relatively smaller SVL (42.21 mm) than O. lineoocellatum (62.11 mm), and had a larger mean clutch size (5.79) than O. lineoocellatum (3.82). There were some differences in diet, although both species consumed a wide range of prey, including spiders, worms, beetles, and millipedes. Z97030