The Global Register of Introduced and Invasive Species - Belgium is a species checklist published by the Invasive Species Specialist Group (ISSG). It contains information on 3,000+ validated non-native taxa in Belgium and serves as the national reference for the Global Register of Introduced and Invasive Species (GRIIS, Pagad et al. 2018). The checklist is created through an open and reproducible workflow developed for the TrIAS project (http://trias-project.be, see Methodology). It is published here as a standardized Darwin Core Archive and includes for each taxon: the scientific name, higher classification and stable taxon identifier, provided by the GBIF Backbone Taxonomy (in the taxon core) and related information in three extensions, provided by the source checklists (or the most trustworthy one in case of competing information). The related information consists of the year of first introduction and last assessment/observation in Belgium and where available its regions (given as a year range in the event date in the distribution extension), coarse habitat information (in the species profile extension) and the pathway(s) of introduction, native ranges (following UN geoscheme), and invasion stage in Belgium (in the description extension). The source for each piece of information is credited. Issues with the dataset can be reported at https://github.com/trias-project/unified-checklist We have released this dataset under a Creative Commons Attribution 4.0 International License (CC-BY 4.0). We would appreciate it if you follow the GBIF citation guidelines (https://www.gbif.org/citation-guidelines) when using the data. If you have any questions regarding this dataset, don’t hesitate to contact us via the contact information provided in the metadata or via https://twitter.com/trias_project. This dataset was published as open data for the TrIAS project (Tracking Invasive Alien Species http://trias-project.be, Vanderhoeven et al. 2017), with technical support provided by the Research Institute for Nature and Forest (INBO).