The Spanish Language Institute is a member of the Costa Rican Evangelical Alliance, a federation that represents the majority of protestant churches and institutions in the country. It is also affiliated with FEDEMEC, a national evangelical mission sending agency, and ACEP, an association of private schools in Costa Rica.

At any one time about 40 different missions and churches, the vast majority of which adhere to a position best described as conservative evangelical, are represented among the student body. Most are members of the Evangelical Foreign Missions Association (EFMA) or the Interdenominational Foreign Missions Association (IFMA).