AbstractUrban environments are critical points for biological invasions because these areas are susceptible to a greater number of environmental disturbances. Because they are densely populated ecosystems, urban environments present a unique opportunity for the involvement of society in the management of invasive exotic species. Similarly, citizen science offers opportunities to conduct research in the field of ecology together with society. The objective of our study was to analyze the occurrence of exotic species in urban areas recorded on iNaturalist and determine whether citizen science applications are good data sources for research projects in invasion ecology. Specifically, we evaluated whether richness and composition of the exotic species community in the cities registered on the iNaturalist platform were explained by socioeconomic and environmental factors. We also verified whether richness of the exotic species in cities registered on the iNaturalist platform were similar to the richness of the exotic species community in the region where the city is located using data collected only by researchers. We obtained 38,374 occurrences of 265 invasive species covering 2,057 cities in 72 countries. Occurrence records were concentrated in North America, Western Europe and Oceania, and there were no data for cities in most of Africa, the Middle East, Eastern Europe and West Asia. Socioeconomic and environmental factors were important determinants of the richness of exotic species in urban areas of the world and were important determinants of the richness of exotic species in natural environments. Urban hotspots of invasive exotic species were different from those for ecosystems in general.