Founded by Onisaburo in 1925, the Aizenkai (Universal Love and Brotherhood Association) serves as Oomoto's secular arm, with nearly twenty branches throughout Asia, as well as in Brazil, Africa, and Micronesia. With the exception of Brazil, membership outside of Japan is wholly made up of local non-Oomoto followers. While the Aizenkai participates in intefaith activities, its main focus is on humanitarian works, ranging from the building of free health clinics in India and Nepal, to organic farming programs in Sri Lanka.

The Aizen Relief Fund uses donated money to provide scholarships for children and to provide disaster relief aid. One of the more successful of the Aizenkai's scholarship programs is a pig-breeding project in the Province of Marinduque, Philippines, that is supplying the seed money to help over 400 elementary school children work their way through school.

Branches