A new species of skink, Kanakysaurus zebratus, is described from the ultramafic Massif de Kopéto and Massif de Koniambo on the northwestern coast of Grande Terre, New Caledonia. Although this new species is similar in overall appearance to its congener K. viviparus from the far northwest of Grande Terre and the Îles Belep, it can be distinguished by features of scalation and coloration. It is also identified as being genetically distinct from and reciprocally monophyletic with respect to populations of K. viviparus from Rivière Néhoué (type population), the Îles Belep, and a recently discovered population from Sommet Poum (reported here for the first time). The population of Kanakysaurus on Dôme de Tiébaghi (5 km southeast of Rivière Néhoué) is problematic: in morphology it is closest to K. viviparus, but DNA sequence data group part of the population with K. viviparus and part with K. zebratus, n. sp. On Kopéto the new species was found only in maquis shrubland at 500–1,000 m in elevation and on Koniambo in Gymnostoma-dominated closed forest at 700 m. Adult females collected on the Massif de Kopéto in February during the height of the wet season had well-developed embryos, confirming a live-bearing mode of reproduction for the new species, and for the genus as a whole. The summit area of Kopéto is the site of a large nickel mine and substantial portions of the known range of the new species are projected to be cleared to extract nickel-bearing ore in the future; extensive development for nickel mining is also forecast in the immediate future for Koniambo. Because of the apparently restricted range and projected degradation of habitat of this new species, it is here regarded as assignable to IUCN Red List Category Endangered and considered a high priority for conservation management.