Tea (Camellia sinensis) is a species of evergreen tree widely cultivated for its leaves, which are used for making beverages. In Japan, there are about 40,000 ha of tea production area, where mainly green tea is produced, including sencha, gyokuro, tencha, kabusecha, and tama-ryokucha. Concerning the origin of Japanese tea, DNA analyses suggest that Japanese tea originated in China. Cultivation of tea plants in Japan presumably started in Kyoto and later spread elsewhere, thereby establishing landraces. Since the Meiji era, various cultivars have been selected from landraces. Many green tea cultivars have been created through crossbreeding. To date, 130 cultivars and breeding materials have been released and registered in Japan, most of which are for green tea. Of these, 67, 8, 11, and 8 are for sencha, kamairicha, gyokuro, and tencha, respectively. Of the sencha cultivars, 45, 10, and 3 cultivars are derived from crossbreeding, individual selection from landraces, and bud sport mutants, respectively. Many gyokuro and tencha cultivars were individually selected from Uji landraces. Japanese cultivars were classified according to timing of budding, disease resistance, and flower morphology. Based on genetic analysis, 44 cultivars were classified into three groups based on their origins: Shizuoka, Kyoto, and China or India. Presently, 95.2% of the tea production area in Japan is occupied by cultivars, of which ‘Yabukita’ accounts for 67.6%. Several cultivars have been bred for properties such as early budding, high pest and disease resistance, diverse aroma and flavor characteristics, and high levels of functional compounds. For example, the cultivars ‘Nanmei’ and ‘Sunrouge’ have been bred to be pest-resistant and to have high levels of anthocyanins, respectively, while the breeding material ‘Cha Chuukanbohon Nou 3’ has been bred to have high levels of tannins and caffeine and a flowery flavor.