A sample of 128 individuals of the slender-toed geckos Nactus spp. from six islands of Papua New Guinea (Bougainville, Fergusson, Misima, New Britain, Rossel, Sudest) was examined for gastrointestinal helminths. Found were one species of Digenea, Mesocoelium brevicaecum; one species of Cestoda, Gekkotaenia novaeguineaensis; one species of Acanthocephala, Sauracanthorhynchus sphenomorphicola; and eight species of Nematoda, Aplectana zweifeli, Bakeria bakeri, Cosmocerca zugi, Meteterakis crombiei, Parapharyngodon maplestoni, Physalopteroides milnensis, Abbreviata sp. (larvae in cysts), Rictulariidae gen. sp. (larvae in cysts). A total of 1,256 helminths was found. Aplectana zweifeli (n = 447), Parapharyngodon maplestoni (n = 238), and Meteterakis crombiei (n = 221) were the most abundant helminths. Ten new host records are reported for Nactus spp. There was a mean of 7.3 ± 3.1 (3–11) helminth species per island. Bougainville Island had the fewest number of helminth species (3) and Misima Island (11) the highest. Nactus spp. are parasitized by generalist helminths that also infect other lizard species.