Leaf margin is important taxonomic trait that has been widely used in many paleoclimatic inferences and biome studies. One of the most significant documented trends in multiple studies using leaf margins is the association between toothy-margined woody Angiosperms and temperate biomes, as well as association between entire-margined woody angiosperms and tropical biomes. Some studies suggest that this leaf-form gradient succeeds a correlation shift through time, from more toothed and tropical early-diverging angiosperm clades, while others suggest that this variation is a result of adaptive environmental convergence in temperate regions. Despite previous research identifying the need to put this global trend in an evolutionary context, not much has been done, with most works focusing on a few species from selected sites or clades. This study provides some insights into the origin and distribution of leaf toothiness in temperate woody angiosperm flora by pooling information from multiple databases, flora, and literature. We collected biome shifts, toothiness, and climate data, and used the resulting phylogenetic trees to analyze the evolution, origin, and geographic distribution of toothiness in temperate woody angiosperm flora. About 232 plant clades have undergone at least one shift between tropical and temperate biomes, and this shift correlates with leaf form. Many temperate woody angiosperm clades independently evolved leaf teeth multiple times, and the geographic distribution of toothiness in most of these clades is associated with regions of low mean annual temperature. This study presents the first documentation of woody angiosperm clades that have undergone shifts between tropical and temperate forests and the origin of toothiness in temperate forests.