Invasive species of anthropological origin pose a significant threat to biodiversity and ecological processes. Scientific evidence has demonstrated that invasion directly causes alterations in the ecosystems of the targeted areas. The introduction of invasive species has led to a substantial decline in the richness of native species and alters advantageous ecosystems in which native species thrive. The severity of the ecological impacts of the invasion is determined by the biological traits of the invading species, especially those associated with its life cycle. The invasion could substantially affect the environment. In particular, when earthworms enter as ecosystem engineers, they significantly modify the ecosystems. For instance, earthworms’ proliferation in an environment where worms were previously nonexistent has a significant impact on the properties of soil, and these modifications may deeply affect the soil species that constitute the bulk of terrestrial biodiversity. Numerous investigations have demonstrated that the presence of invasive earthworms in an area leads to a decrease in both the plentitude and variety of soil invertebrates. Earthworm introduction affects microbial populations and the nitrogen cycle in the invaded ecosystems. Research findings indicate that the proliferation of earthworm populations adversely affects the diversity of native plant species in the region. The introduction of earthworms generally leads to a reduction in the overall diversity of plant species present. This chapter aims to elucidate the impact of introduced earthworms on different native organisms in affected regions.