Three new species of Phyllocnistis Zeller are described from the central highlands of Costa Rica: Phyllocnistis drimiphaga sp. n., P. maxberryi sp. n., and P tropaeolicola sp. n. Larvae of all three are serpentine leaf miners. Phyllocnistis drimiphaga feeds on Drimys granadensis (Winteraceae), P maxberryi on Gaiadendron punctatum (Loranthaceae), and P tropaeolicola on Tropaeolum emarginatum (Tropaeolaceae). All specimens were collected as larvae or pupae in their mines and reared in captivity. Parasitoid wasps were reared from P drimiphaga and P maxberryi. Description of the adults, pupae, and life histories are supplemented with photographs, illustrations, and scanning electron micrographs.