Gansaini (year of birth and death unknown) was a nun (Buddhist nun) of the Tendai sect in the mid Heian period. Gansaini's father was Masachika URABE, her mother came from the Kiyohara clan and she was the older sister of her brother Genshin (a priest) and sister Ganshoni. There is another theory that she and her younger sister Ganshoni were the same person.
After becoming a nun, she earnestly read the Hoke-kyo Sutra (the Lotus Sutra) and prayed to the Amida Buddha. While she adhered to the precepts of Buddhism and distributed her offerings among poor people, she was reportedly content with living in poverty. Gansaini allegedly died during the Kanko era (1004-1012). Her strong faith seemed to be well-known at that time.