This paper reviews the alien (non-native, non-indigenous, exotic) true bug (Heteroptera) species in Europe. Forty-two established alien Heteroptera are recognized, of which 12 species are alien to Europe (originating outside Europe: eight from North America, three from the Eastern Palaearctic, one from New Zealand), 24 species are alien within Europe (translocated within Europe), and six ... [Show full abstract] cryptogenic species are of unknown origin. Since 1990 an approximate arrival rate of 7 species per decade has been observed. A recent trend of increased introductions from North America to Europe is suggested. The most important pathway of alien Heteroptera is translocation as contaminants (49 %), usually with ornamental plants, followed by unintentional introduction through natural dispersal (unaided) across political borders within Europe (28 %), and translocation as stowaways within a transport vector (21 %). The taxonomic composition of the alien Heteroptera of Europe is dominated by Miridae (17 species, 40 %), Tingidae (8 species, 19 %), and Anthocoridae (5 species, 12 %), all of which are overrepresented compared to the native European Heteroptera fauna. More than half of the species are phytophagous (24 species, 57 %) and the advantage of trophic specialization in invasion success is discussed. Most species are currently known to occur in the Czech Republic (19 species) and Germany (17 species), followed by Western European countries (Belgium 15 sp., France and United Kingdom 14 sp. each, and Netherlands 13 sp.), resulting in an apparent (north)west-(south)east gradient probably reflecting horticultural tradition in Europe. No unambiguous evidence exists so far for negative ecological or economical impacts, but more research is needed to investigate possible effects. Introductions of alien Heteroptera to and within Europe will increase, and deserve further consideration.