Following a request from the European Commission, the EFSA Plant Health Panel performed a pest categorisation of Lopholeucaspis japonica (Hemiptera: Diaspididae), an armoured scale which preferentially feeds on smooth barked woody trees and shrubs. The pest occurs in Asia, North America and non-EU Europe (Caucasus region and Ukraine). The pest is regulated in Council Directive 2000/29/EC as Leucaspis japonica, a junior synonym. Its introduction into the EU is banned on plants of Citrus, Fortunella, Poncirus and their hybrids, other than fruit and seeds. Additional host plants comprise 60 species in 35 botanical families, including deciduous fruit trees, ornamental and forest plants. L. japonica could enter the EU via host plants for planting (excluding seeds) and cut branches. It has been intercepted on plants for planting from China, including artificially dwarfed plants. Spread is most likely via plants for planting, rather than via natural spread as most diaspidid life stages are sessile. Impacts could occur in citrus, other fruit crops, ornamentals and forest trees. Sourcing plants from pest-free areas, pest-free places of production or pest-free production sites would decrease the likelihood of introduction. Because suitable hosts occur across the EU in climatic areas matching those where the pest is known to occur, biotic and abiotic conditions are conducive to establishment. The main uncertainty concerns its current distribution in the EU. L. japonica was found in Greece in 1983, but there have been no other reports since then. L japonica satisfies the criteria assessed by EFSA that enable it to be considered a potential quarantine pest. L. japonica does not satisfy the criteria assessed by EFSA for it to be considered a potential regulated non-quarantine pest (RNQP).