Data information to the paperBoonman, C.C.F. et al. (2021) Plant functional and taxonomic diversity in European grasslands along climatic gradients. Journal of Vegetation Science. DOI: 10.1111/jvs.13027Here, we discuss how both functional and taxonomic diversity of European grasslands change along temperature and precipitation gradients. We compare trends and discuss functional richness effect sizes which correct functional richness values for local taxonomic richness. Specifically, assessed the variation along a minimum temperature, annual temperature range, annual precipitation, and precipitation seasonality gradients.Species occurence data was collected from the European Vegetation Archive. This data was linked to trait data from the TRY database. We used species averages of specific leaf area (SLA), leaf nitrogen concentration (LNC), plant height, seed mass, specific root length (SRL), and rooting depth (i.e., not including intraspecific trait variation). Gaps of missing trait data was filled using the ‚mice‘ function of the mice package. Per plant community, taxnomic richness (number of species) was calculated. Further, the functional richness was calculated as the convexhull volume (see paper for more details). And effect sizes were calculated with a null model which randomly shuffles species trait values in the trait dataset but retains species’ trait combinations.For the European analysis, we used the average of the original functional richness values and effect size values in one grid cell (~1 km2) if more than one plot was sampled. This resulted in 19,179 data points and grid cells that were regressed along climate variables using a multiple general additive modelling approach.The data files include diversity data, longitude and latitude, and various climate variables. In addition, we included two Rscripts that calculate the functional richness effect size. The README.txt describes all files in more detail.