Niche overlap – which describes how similar ecological (or climatic) niches are between species is a pillar of modern theory of species coexistence and is frequently used to better understand the proximate drivers of large-scale biodiversity patterns. Yet, measures of niche overlap are usually limited to specific taxonomic groups and/or location.We coupled IUCN range maps with bioclimatic variables to estimate the extent to which the climatic niche and the geographic range of more than 18,000 species were overlapping, leading to 100,670,955 assessments on lands and 7,282,836 assessments in oceans. All these measures are grouped into one unique database called BioOverlap.