Oomoto (大本 Ōmoto, literally "foundation"), also known as Oomoto-kyo (大本教 Ōmoto-kyō), is a Japanese religion, often categorized as a new Japanese religion originated from Shinto. Deguchi Nao (1836–1918) was its kaiso (original founder) in 1892. The spiritual leaders of the movement have predominantly been women; however, Deguchi Onisaburō (1871–1948) has been considered an important figure in Omoto as a seishi (spiritual teacher).
Since 2001, the movement has been guided by its fifth leader, Kurenai Deguchi.
From 1925 until 1933 Oomoto maintained a mission in Paris. From there, missionaries travelled throughout Europe, spreading the word that Onisaburo Deguchi was a Messiah or Maitreya, who would unify the world.