The talk will summarize the results of our research on alien vascular plant species in Iceland. The research was designed to achieve the following aims: (1) To provide up-to-date information on vascular alien plants in Iceland, (2) To define spatial patterns of alien plants in Iceland and to identify hotspots of alien plant diversity, (3) To define major environmental factors that have an impact on alien plant distribution in Iceland, (4) To predict the impact of climate change on alien flora in Iceland.We evidenced the presence of 336 alien vascular plant taxa, including 277 casuals and 59 naturalised taxa (2 invasive taxa). Using GIS analytical tools we evidenced that distribution of alien flora exhibit a clear spatial pattern showing hotspots of occurrence and diversity within areas of major settlement centres. Altitude above sea level and temperature-related variables were proved to be the most important factors shaping alien plant distribution in Iceland. Predictive modelling experiments carried out using maximum entropy approach evidenced that arctic areas of Iceland and the Central Highlands are under serious risk of alien plant invasion due to climate change.