A coherent response to biological invasions involves science-based, up-to-date prioritization tools alongside information transfer to relevant authorities and stakeholders. Here, we describe how the collaboration between scientists and policy makers in Belgium has allowed the development of decision support tools regarding invasive alien species. We present the environmental impact assessment protocol ISEIA and comment on its applications. Furthermore, we describe and provide metadata for the information system Harmonia which was developed to disseminate this information to a diverse audience. Using several examples of initiatives addressing the threat of invasive alien species in Belgium, we show how these tools have been instrumental in strengthening capacity of the scientific community, authorities and stakeholders in Belgium on addressing the invasive alien species issue.