Isertia is a genus of flowering plants in the family Rubiaceae. It has 14 species, all indigenous to the neotropics. They are shrubs or small trees. A few are cultivated as ornamentals. The type species for the genus is Isertia coccinea. Isertia was named by Johann von Schreber in 1789. The generic name honors the German botanist and explorer Paul Erdmann Isert. Molecular phylogenetic studies have shown that Isertia is most closely related to Kerianthera, a monospecific genus from Amazonian Brazil.