This chapter delves into the pervasive threat of invasive alien species (IAS) to global biodiversity. IAS are often introduced unintentionally through trade and travel, and then they infiltrate new ecosystems; as a consequence of their presence, they unsettle the delicate balance of native flora and fauna. The chapter unfolds a comprehensive exploration of the multifaceted impact of IAS, ranging from competition for resources to the contamination of water bodies, ecosystem imbalance, and irreversible ecological changes. Drawing from global case studies, it emphasizes the far-reaching consequences of IAS invasions, highlighting the vital role of citizen science and community-driven data models in tracking their spread. These case studies also give information about the origin of invasive species such as Asian carp, marine toads, zebra mussels, and European starling along with major affected countries. IAS’s economic and agricultural repercussions are also scrutinized, underscoring their capacity to reshape the entire ecosystems. The chapter outlines a spectrum of management strategies such as prevention, early detection, rapid response, control, and eradication, with long-term policies and spatially explicit models guiding efforts for maximum effectiveness, in response to this formidable challenge. It underscores the importance of proactive and coordinated action, from horizon scanning and risk assessments to preventive measures, eradication efforts, and long-term policies. Here we have outlined the global organizations that have taken steps to counter the rising threats from the undesirable spread of exotic species. Spatially explicit models and improved data flows are pivotal for effective IAS management. Ultimately, this chapter underscores the imperative nature of collaborative, awareness-driven responses to combat the persistent menace of IAS and safeguard global biodiversity.