St Mary’s School, Waverley, has an established and active Old Girls’ Association. The association, founded in 1929, is an integral part of the St Mary's School community. The association provides a link between the school, past pupils and the greater school community. It aims to foster and strengthen the alumni network, uphold the St Mary’s values of love, community and integrity and support the school to ensure our children’s children may also enjoy all that St Mary’s has to offer. Old Girls, who are members of the association, receive communication regarding events arranged and hosted by both the association and the school, as well as important information pertaining to the school.

The school wants to keep in touch with its alumni and encourages them to join the association.