Old Josephians Association (OJA) represents all former students of St. Joseph's School. The Association is active in promoting fellowship among "old boys and girls" of the School and helps establish links between former students and the Alma Mater.

In recent times the OJA has also sponsored activities to reconnect former students to the Alma Mater through sporting events between former and present students, sponsoring and organizing fund raising for the world renowned SJS Brass Band to enable it to compete in the international arena.

The Ora et Labora Run is another event organized by the OJA to raise funds to repair, restore and to help preserve the iconic Mill Hill Block which was built almost a hundred years ago.

This year is the 135th Anniversary of the establishment of St. Joseph's School. A grand dinner will be held in November to celebrate this momentous year. It will also be a fund raising occasion for the OJA and the School to raise some money for the repair and restoration of the School's Mill Hill Block.

The OJA encourages students and the public to donate generously to support an institution which had been so much a part of the educational development of Sarawak in particular and Malaysia in general.