The Diocesan Old Girls' Association has been active since 1926. The Association had, for many years, been registered as an 「unincorporated association」 under the Societies Ordinance. In 2001, the association was corporatized and reorganised into 2 arms:
- Diocesan Old Girls' Association Limited (also known as DOGA), a company limited by guarantee; and
- Diocesan Old Girls' Association Foundation Limited (also known as Foundation), a subsidiary of Diocesan Old Girls' Association Limited and a company limited by shares, which is also registered as a charity under Section 88 of the Inland Revenue Ordinance.
The principal activities of DOGA are to facilitate fellowship amongst old girls through social gatherings and interest group activities, foster close relationships between past and present students and to support the School and existing students of DGS and DGJS by the provision of scholarships and other assistance including mentoring and career guidance. The Foundation has charitable objects and makes donations to the School and other charities on an ad hoc basis.