Shuei (809 - April 29, 884) was a Shingon Sect Buddhist monk who lived during the first part of the Heian period. He was born into the Odani clan. He came from Kyoto. His name can be pronounced either 'Shuuei' or 'Shuei'. He was one of the eight priests (Saicho, Kukai, Jogyo, Engyo, Ennin, Eun, Enchin and Shuei) who travelled to Tang Dynasty China.
At age 14, he went to Mt. Hiei where he entered the Buddhist priesthood under Saichin before later learning the Hosso Sect teachings from Gien of Kofuku-ji Temple, the Tendai Sect teachings from Gishin of Enryaku-ji Temple, Diamond Realm and Womb Realm mandalas from Enchin, Shingon Sect teachings from Jitsue, and being consecrated by Shinsho of Zenrin-ji Temple (Kyoto City). In the year 862, he travelled to Tang Dynasty China with Cloistered Imperial Prince Shinnyo. He made pilgrimages to Mt. Wutai and Mt. Tiantai and studied esoteric Buddhism under monks including Xuanqung of Bianzhou and Faquan of Changan before returning to Japan in the year 865. Shuei was promoted to Gon-Risshi (generally in Shingon sect, fifteenth-ranking Buddhist priest, literally, "supernumerary master of discipline") in 869, and in the year 879 was successively appointed Sojo (high-ranking Buddhist priest), betto (administrator) of Todai-ji Temple and second abbot of To-ji Temple. He received the devotion of Emperor Seiwa and served as kaishi (the priest who imparts the Buddhist commandments) when the emperor entered the priesthood.