Waarnemingen.be - Butterfly occurrences in Flanders and the Brussels Capital Region, Belgium is a species occurrence dataset published by Natuurpunt and described (v1.4) in Maes et al. (2016, https://doi.org/10.3897/zookeys.585.8019). The dataset contains close to 1.3 million butterfly (Lepidoptera excluding moths) occurrences of 69 naturally occurring species (native, vagrant or migrant species), recorded by volunteers (citizen scientists), mainly since 2008. Together with the dataset Maes et al. (2016, https://doi.org/10.15468/njgbmh), it represents the most complete overview of butterflies in Flanders and the Brussels Capital Region (north Belgium). The occurrences are derived from the database http://www.waarnemingen.be, hosted at the nature conservation NGO Natuurpunt in collaboration with Stichting Natuurinformatie. Standardized information regarding the occurrence's sex, lifeStage, behavior, occurrenceRemarks, and samplingProtocol is included as well. Generalized and/or withheld information: location ...