Forests with different ? ora and vegetation types harbor different assemblages of ? ower visitors, and plant – pollinator interactions vary among forests. In monsoon-dominated East and Southeast Asia, there is a characteristic gradient in climate along latitude, creating a broad spectrum of forest types with potentially diverse pollinator communities. To detect a geographical pattern of plant– p ollinator interactions, we investigated ? owering phenology and pollinator assemblages in the least-studied forest type, i.e., tropical monsoon forest, in the Vientiane plain in Laos. Throughout the 5-year study, we observed 171 plant species blooming and detected ? ower visitors on 145 species. Flowering occurred throughout the year, although the number of ? owering plant species peaked at the end of dry season. The dominant canopy trees, including Dipterocarpaceae, bloomed annually, in contrast to the supra-annual general ? owering that occurs in Southeast Asian tropical rain forests. Among the 134 native plant species, 68 were pollinated by hymenopterans and others by lepidopterans, beetles, ? ies, or diverse insects. Among the observed bees, Xylocopa , megachilids, and honeybees mainly contributed to the pollination of canopy trees, whereas long-tongued Amegilla bees pollinated diverse perennials with long corolla tubes. This is the ? rst community-level study of plant – pollinator interactions in an Asian tropical monsoon forest ecosystem.