Kakuen (1031 - May 19, 1098) was a Tendai Sect Buddhist monk who lived during the latter part of the Heian period. His father was FUJIWARA no Yorimichi. He is also known as Uji no Sojo.
Kakuen entered the Buddhist priesthood and studied exoteric Buddhism and esoteric Buddhism under Myoson of Onjo-ji Temple (Mii-dera Temple). He was promoted to the rank of Gon no Shosozu in 1054, appointed Chori (chief priest) of Onjo-ji Temple in 1063, and made Daisojo (highest rank of a Buddhist monk) in 1065. In 1077, he was appointed Tendai Zasu (head priest of the Tendai Sect) by imperial charter but was forced to resign after only three days in the face of opposition from the followers of Enryaku-ji Temple; being made betto (administrator) of Hossho-ji Temple instead. He later conducted esoteric prayer rituals at the imperial palace and it is said that he performed amazing miracles. He had the deep trust of the imperial court as well as nobility, and was granted "gissha no senji" (special permission from the emperor to enter the imperial palace in an ox-drawn cart) in January 1096. Recent investigations have led to debate over the theory that he died in the year 1099.