Inventory of the terrestrial isopods in Belgium (2011-2020) is an occurrence dataset published by Spinicornis (Terrestrial Isopod Research Group of Belgium), the Research Institute of Nature and Forest (INBO) & Natuurpunt Studie. The dataset represents the most complete overview of terrestrial isopods in Belgium and includes occurrences of 35 species, observed between 2011 and 2020. There are 36 native terrestrial isopod species in Belgium (De Smedt et al. 2018) and only one (i.e. Miktoniscus patiencei Vandel, 1946) hasn’t been detected in Belgium between 2011 and 2020. The occurrences originate from field surveys, pitfall trap projects and casual observations. The recorded data are registered through the citizen science portals waarnemingen.be and observations.be, managed by Natuurpunt Studie and Natagora respectively. All data were verified by experts. Here, the dataset is published as a standardized Darwin Core Archive and includes for each record an occurrenceID, reference, date, location and scientific name and if available also individual count, sex, lifestage, behavior, sampling protocol and information on the identification. Generalized and/or withheld information: location information is generalized to 5 x 5 km² Universal Transverse Mercator (UTM) grid cells. Observer name, exact XY-coordinates, toponyms, and photographs are not included in the published dataset, but are known in the source database. To allow anyone to use this dataset, we have released the data to the public domain under a Creative Commons Zero waiver (http://creativecommons.org/publicdomain/zero/1.0/). We would appreciate however, if you read and follow these norms for data use (http://www.natuurpunt.be/normen-voor-datagebruik) and provide a link to the original dataset (https://doi.org/10.15468/mw9c66) whenever possible. If you use these data for a scientific paper, please cite the dataset following the applicable citation norms and/or consider us for co-authorship. We are always interested to provide more information and available for help with analysing the data for your project, so please contact us via the contact information provided in the metadata or via pepijn@spinicornis.be.