This study aims at finding the effectiveness of guidance and counselling through Gestalt Game technique in improving students’ adaptability in two Islamic boarding schools. The study was conducted by using a pretest-posttest nonequivalent group design involving four groups of students from two different Islamic boarding schools. The study considered the influnce of gender and boarding school environment towards the effectiveness of Gestalt Game. It was conducted by controlling heterogenity in students’ adaptability before the treatment as well as students’ religiosity. The study shows that Gestalt Game is effective in improving adaptability of the students in the two Islamic boarding schools involved in the study. Moreover, the study reveals that Gestalt Game does not affect gender and Islamic boarding schools’ environment. Keywords: Gestalt Game; students’ adaptability; students’ religiosity