Abstract <p>Chrysomelidae comprises a highly diverse family of phytophagous beetles that play key roles in ecosystems. Despite their ecological importance, leaf beetles remain understudied in megadiverse tropical regions such as Ecuador. The aim of this study is updating the knowledge on the diversity of Chrysomelidae in Ecuador by: (i) compiling literature and Global Biodiversity Information Facility (GBIF) records; (ii) evaluating temporal, spatial, and taxonomic biases on these data; (iii) exploring spatial patterns of species richness; and (iv) estimating the potential diversity of Chrysomelidae in Ecuador through modelling the distribution of chrysomelid species from Mexico to Paraguay, and using known ratios between plant and leaf beetle species richness from Ecuador, Brazil, El Salvador, Mexico, and Peru. We compiled a dataset of 2,348 records of 871 leaf beetle species from Ecuador, representing different degrees of temporal, spatial, and taxonomic biases. The potential richness of Chrysomelidae in Ecuador shows a clear spatial pattern, with the highest number of species predicted for the extreme NE and NW regions, while this number decreases towards the south and in the inter-Andean valleys. Species distribution models estimated the potential presence of 42 chrysomelid species not previously recorded in Ecuador. Furthermore, the comparison of leaf beetle-vascular plant richness ratios in Ecuador with those of Brazil, El Salvador, Mexico, and Peru, suggests that the actual diversity of Chrysomelidae in Ecuador may be 2–3 times higher than currently known.</p> Implications for insect conservation <p>This work improves the knowledge of species diversity of Chrysomelidae in Ecuador, essential information for developing effective conservation strategies for this diverse beetle family, but much more field inventories are still needed.</p>