This is a case study research that is trying to identify a social interaction among multi ethnic students to maintain national integration. This research is concern on the factors that influence social interaction among students through co-curriculum activities like participate in sports and clubs at school. Findings from interview session individualy and grouping at two secondary schools at Kuala Ketil, Kedah shown there is a conflict and stereotype among students, however feeling to learn and accept the differences within ethnics still exist. Throughout the research, it shows that factors from external influence comes from school and peer groups. However, in the part of internal influence it is from student’s intrapersonal factor. In order to maintain social interaction among students, strategies had been taken by school through co-curriculum activities like sports and clubs. As a conclusion, a good social interaction among multiethnic students very important and need support from school’s administrator to maintain and sustain the harmonius and glory of the nation.