Seed production in rice (Oryza sativa L.) largely depends on the number of flowers, which is in turn regulated by the inflorescence architecture. The developmental process of inflorescence and spikelet in grasses including rice differs considerably from that in other monocotyledonous and dicotyledonous species, and rice, an important crop plant, is often used as a model monocot plant. Nevertheless, the developmental course of wild-type rice has not yet been well characterized. Thus, detailed description of rice inflorescence and spikelet development would be valuable for characterizing mutant phenotypes and also for comparing rice with other grass species. In this study, we showed a number of landmark events in the developmental courses of inflorescence and spikelet, and divided their development into nine and eight stages, respectively. This staging system would be useful as a reference for developmental description.