St. John de Britto Institute also referred to by its acronym ISIB or by its Portuguese name Instituto São João de Brito is a private Catholic coeducational higher education institution run by the Timor-Leste Region of the Society of Jesus in Kasait-Ulmera, East Timor.

The school was named after St. John de Britto, a Portuguese Jesuit missionary and martyr.

[2][3] In 2017 ISIB operated out of classrooms of Loyola in Kasait as construction began there of its own facility.

[5] The school cooperates with other Jesuit works[6] in the country: a mission parish with secondary school and health care program in Railaco,[7] a public service Audiovisual Production House,[8] and Jesuit Social Service Timor-Leste which aims to foster volunteerism, strengthen communities, and facilitate networking.

It offers a four-year program aimed at producing professional high school teachers.