Marist Old Students Association (MOSA) is a non-political and non-governmental Organization of the former students of Marist Brother Secondary Dete, Zimbabwe (MBSS). The organisation was formed to unite and forge ahead in promoting and fostering the growth and development of the former school and integrating those who share in the MOSA vision. This association or organization is a network of former and current MBSS students and teachers and those who share the same vision in the growth and development of the school world over. Membership is open to any person who may be connected to the school in one way or another. A mere interest and love of the school is but adequate qualification for one to take part in the discussions. The aims of the organisation are to seek ways of improving the standards of education, general conduct and to provide carrier guidance to those still studying at the school.
Vision: The vision of MOSA is to help the school/former school (MBSS) in its growth and development so that it may continue to produce a proud, useful and distiguished service persons -- persons who will not only be of good and useful service to the school but humanity as a whole, that is, Zimbabwe, Africa and the World.