Five species of Psyllinae are recognised from Gunung Kinabalu, all previously unknown, and are formally described and named: Cacopsylla graciliforceps sp. nov., C. kinabaluensis sp. nov., C. myrsines sp. nov., C. photiniae sp. nov. and Psylla cirrita sp. nov. Another species similar to P. cirrita remains undescribed due to lack of sufficient material. Two Philippine species closely related to C. kinabaluensis are transferred to Cacopsylla as Cacopsylla aranetae (Miyatake, 1972), comb. nov. and Cacopsylla bakeri (Crawford, 1919), comb. nov. (both from Psylla). Three of the Cacopsylla species probably represent Palaearctic faunal elements (Cacopsylla graciliforceps, C. myrsines and C. photiniae). Host information is available only for Cacopsylla myrsines and C. photiniae, viz. Myrsine dasyphylla (Primulaceae) and Photinia davidiana (Rosaceae), respectively. Myrsine has not been previously reported as host genus of Psylloidea. The five new species bring the number of known Psylloidea species from Gunung Kinabalu to 22. The biogeographic relationships found in the flora, i.e. Oriental elements predominate at lower altitudes, and Himalayan and Australian elements are dominant at altitudes above 2500 m, are reflected in the psyllid fauna (Oriental 4 spp.; Australian 13 spp., Himalayan 3 spp.; unknown 2 spp.). Of the 22 species known from Gunung Kinabalu, 18 are only known from there. This high number is probably only partly due to endemism and is partly due to insufficient knowledge of the psyllid fauna of Borneo and of the tropics in general.