Three new species of gall-forming psyllids (Hemiptera: Psylloidea) in the families Triozidae and Phacopteronidae are described from Papua New Guinea: Trioza incrustata Percy, sp. nov. makes enclosed leaf margin galls on Celtis philippensis (Cannabaceae), Trioza grallata Percy, sp. nov. makes enclosed leaf surface galls on Elaeocarpus schlechterianus (Elaeocarpaceae), and Cornegenapsylla allophyli Malenovský and Percy, sp. nov. makes enclosed leaf margin galls on Allophylus cobbe (Sapindaceae). Descriptions of the adult and immature morphology for these new species are provided, and differences in adult and immature morphology between Cornegenapsylla allophyli and Cornegenapsylla sinica Yang and Li, 1982 (the type species of Cornegenapsylla) are illustrated. We report new records for Papua New Guinea of Pseudophacopteron tuberculatum (Crawford, 1912) on Alstonia sp. (Apocynaceae), Pauropsylla triozoptera Crawford, 1913 on Ficus trachypison (Moraceae) and Pauropsylla udei Rübsaamen, 1899 on Ficus variegata, with descriptions of the variation found in the latter two widespread Asian species. Pauropsylla reticulata Mathur, 1975 is synonymized with P. udei. Mitochondrial DNA barcodes for the new species, as well as for P. triozoptera and P. udei are provided.