The aim of the research was to present current data on the distribution and development of some alien phytophagous insects in the territory of Ukraine.We considered 19 species of alien phytophagous insects, including 2 species of Coleoptera, 7 Hemiptera (including 4 bug species), 7 Lepidoptera, 2 Hymenoptera, and 1 Diptera. Hyphantria cunea penetrated Ukraine about 70 years ago and sometimes outbreaks in orchards or shelterbelts. Cameraria ohridella and Cydalima perspectalis pose a great threat to Aesculus hippocastanum and Buxus sempervirens, respectively, in urban stands. Parectopa robiniella, Macrosaccus robiniella, Nematus tibialis, and Obolodiplosis robiniae did not attract the attention of researchers until recently, since did not show a noticeable effect on the health condition of Robinia pseudoacacia. Phyllonorycter issikii is not abundant in most parts of Ukraine. Phyllonorycter platani and Corythucha ciliata are not serious pests because their host plant (Platanus sp.) is rather rare in Ukraine. Trichoferus campestris is known long ago but has not yet shown any harmful effects. The threat from sucking insects (aphids and bugs) increases due to their ability to vector tree pathogens. The polyphagous Halyomorpha halys can pose a threat to forest, ornamental and agricultural plants. Leptoglossus occidentalis poses a great danger to the restoration of Scots pine forests because its feeding decreases the seeds’ germination. Corythucha arcuata is found only in two regions but is moving northward and may pose a threat to oak stands. Agrilus planipennis has spread over several years from the eastern border with Russia to the entire Luhansk and partly Kharkiv region, inhabits Fraxinus excelsior and F. pennsylvanica, and can move west.