Tropical dry forest is a biome characterized by prolonged dry seasons which harbors an exceptionally rich floristic biodiversity. Yet it is among the most threatened biomes and its belowground diversity remains poorly documented. Here, we analyzed the soil environmental DNA with metabarcoding to quantify the belowground diversity and composition of 11 tropical dry forest sites across four biogeographic regions in Colombia, and we provide a comparative analysis of the biogeographic drivers of soil biodiversity, including soil properties, climate, and spatial factors. We found that the soil microbial communities of tropical dry forests had high proportions of taxa associated with dry conditions, such as Actinomycetota, Glomeromycetes, and Amoebozoa, compared to other tropical forests. Soil mesofauna consisted mainly of ants, termites, and earthworms, with few enchytraeids. The soil microbial alpha and beta diversity were primarily driven by soil physicochemical and climatic drivers,...