Rajagiri Old Students Association (ROSA) was conceived in the minds of a handful of alumnae in the year 1986. The Association was officially constituted on 2nd October 1986 under the guidance of the then Headmaster, Rev. Fr.Pynadath. These far sighted persons were of the view that the camaraderie developed in the school should continue in later years and also that the alumnae should work for the betterment of the school and coordinate projects for the benefit of the present students.
Dr.George Koluthara was the first President of ROSA followed by Mr. Regin Chalapuram, Mr.Dalby Benny, Mr.Jose Kuttan and Mr.Joby Tharian. Dr.Davis Akkara is the current President of ROSA.
Students of the School are eligible to become members of ROSA, seven years after passing out of Std X. At present there are about 120 Life Members and 700 ordinary members. An Executive Committee controls the Association. A genuinely interested member can apply to become an Executive Member.