The research applied a qualitative method in the collection of data by conducting semi-structured, in-depth interviews. A total of six cities in Indonesia were selected as research sites. By taking these considerations into account, 40 schools were selected as research samples (i.e. purposive sampling). From October 2-21, 2017, a total of 440 informants were interviewed as resource persons. The key findings obtained of the study: the radicalism taking place at schools has been met with a response from religiously moderate groups; the overlap and ambiguity of OSIS umbrella regulations have led schools to reduce OSIS activities to pertain to religious strengthening only and highly discriminative or being irrelevant to minority groups; and the lack of understanding and awareness of schools regarding the map of radical movements has undermined the school residents’ resistance mechanism against radicalism.