Thrips (Order Thysanoptera) are found worldwide and include almost 6000 species. Several of them are notorious for causing extensive crop damage (by feeding on leaf tissue or by vectoring viral disease). Their small size (usually less than 2 millimeters) and cryptic habits have facilited invasions and establishment in Europe in the wild or in greenhouses. Fifty-two alien species, belonging to four families have been recorded within Europe. Species introduced before 1950 mostly originate from America, tropical and subtropical areas and subsequent arrivals generally originate from Asia (and from America to some extent). Five countries host more than 30% of the European alien thrips fauna and two alien thrips occur in more than 50% of the countries and islands of Europe.