Insects are among the world’s most ecologically and economically important invasive species. An international group collaborating with the Forest Service’s Northern Research Station assembled inventories of native and non-native species from 20 world regions and contrasted relative numbers among regional species assemblages. Research suggests that the distribution of species among insect orders is completely different between native and non-native assemblages. Some orders, such as the Psocoptera, Dictyoptera, Siphonaptera, Thysanoptera, and Hemiptera, are always over-represented in the non-native compared to native assemblages. Other orders, such as the Plecoptera, Trichoptera, Ephemeroptera, Odonata, Mecoptera and Microcoryphila, are consistently under-represented in non-native assemblages. These patterns likely arise both as a result of variation among taxa in their association with invasion pathways responsible for transporting species among world regions, as well as variation in life-history traits affecting establishment potential. Study results indicate that species compositions associated with invasiveness are fundamentally different from compositions related to insularity, indicating that colonization of islands selects for a different group of insect taxa than does selection for successful invaders. Native and non-native assemblage compositions were also related, to latitude of the region sampled. Together, these results illustrate the dominant role of invasion pathways in shaping the composition of non-native insect assemblages.