The EFSA Panel on Plant Health performed a pest categorisation of Matsucoccus matsumurae (Hemiptera: Matsucoccidae), the Massonian pine bast scale, for the EU territory. This pest categorisation was initiated following the commodity risk assessment of artificially dwarfed plants from China consisting of Pinus parviflora (Japanese white pine) grafted on P. thunbergii (Japanese black pine) performed by EFSA, in which M. matsumurae was identified as a pest of possible concern. However, its identity is not firmly established due to uncertainty regarding its taxonomic relationship with Matsucoccus pini (Green), a species widespread in Europe. M. matsumurae occurs in western China and has been reported as a pest of P. massoniana (Chinese red pine) and P. thunbergii. These hosts occur in the EU as ornamental/amenity trees. Other scales in the Matsucoccus genus feed on a variety of Pinus species and the host range of M. matsumurae could be wider than is currently recorded. The scale has one or two generations per year. All stages occur on the branches and stems of hosts with developing nymphs and adult females feeding through the bark on host phloem vessels. Symptoms include the yellowing/browning of host needles, early needle drop, desiccation of shoots and bark necrosis. The most serious infestations occur in hosts that are 8–25 years old and there can be some host mortality. In principle, host plants for planting and plant products such as cut branches and wood with bark could provide entry pathways into the EU. However, prohibitions on the import of Pinus from non-European third countries regulate these pathways. In China, M. matsumurae occurs in regions with temperate humid conditions and hot summers. These conditions are also found in parts of southern EU. Were M. matsumurae to establish in the EU, it is conceivable that it could expand its host range; however, this remains uncertain. Some uncertainty exists over the magnitude of potential impacts. M. matsumurae satisfies the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest, assuming M. pini is not a synonym, which is a key uncertainty.