The main purpose of this paper is to provide an overview of the distribution and invasive status of non-native plant species in Italy, divided according to its administrative regions, biogeographic regions and land use types, and a synthesis of current knowledge on the impacts posed by these species within the country. More specific aims are: to present summarised information on the structure of Italian regional alien floras, to outline the main overall geographic patterns of plant invasion across Italy and to reveal the main large-scale environmental factors that influence the number of alien species in individual regions.