The genus Lespedeza (Fabaceae) contains about 41 species distributed disjunctly in East Asia and North America. The pollen morphology of 46 samples representing 39 species of Lespedeza and three species of the two most closely related genera from China, Japan, and America was examined with both a light microscope and a scanning electron microscope. Pollen morphology in Lespedeza is diverse in germination organs and exine sculptures. The germination organs in Lespedeza can be divided into three types based mainly on the size of the colpi and the morphology of ora. Most species in subgen. Lespedeza have either type II or III germination organs and species in subgen. Macrolespedeza have only type I or II germination organs. The pollen morphology in Lespedeza is stable at the infraspecific level. The pollen data support the division of Lespedeza into two subgenera. In detail, the polar axes in subgen. Macrolespedeza (18.94–23.07 µm long) and are normally shorter than those in subgen. Lespedeza (25.04–32.11 µm long). The pollen morphology provided insights into the systematics of some taxonomically difficult species complexes such as the L. caraganae, L. juncea, and L. inschanica complex and the L. pubescens, L. viatorum, and L. wilfordii complex and the species pairs L. floribunda and L. mucronata and L. angustifolia and L. leptostachya. A key to the species of Lespedeza is given based on pollen morphology.