The Cranbrook School Parents' Association (CSPA) was set up to formalise and improve social and fundraising relationships between the School and parents.

The CSPA is a member of the National Confederation of Parent Teacher Associations (NCPTA) and has adopted their model constitution.

The CSPA is registered with the Charity Commission. As a charity the object of the Association is to advance the education of the pupils in the school. In furtherance of this object, the Association may:
1. develop more extended relationships between the staff, parents and others associated with the school;
2. engage in activities which support the school and advance the education of the pupils attending it;
3. provide and assist in the provision of facilities for education at the school.

The CSPA consists of an Executive Committee and three permanent sub-committees, plus further temporary sub-committees as are from time to time required. Under the terms of the Constitution the Executive Committee may have up to 20 members and a further 10 members may be co-opted by this committee to support the sub-committees.

The Executive Committee includes the Chairman, the Vice-Chairman, the Honorary Secretary and the Honorary Treasurer. Members of the Executive Committee act as chairmen of the sub-committees, House Representatives' coordinator, Helping Hands coordinator, Coach House Café coordinator and Year 9 coordinator. The Committee meets twice a term to consider reports of the sub-committees and other matters arising. Meetings are attended by the Head Teacher, a staff representative and a representative of the Governors.

The sub-committees are Spending, Fundraising, Education. Terms of reference for these committees have been prepared, and are updated from time to time, by the Executive Committee. Sub-committees normally meet twice a term to plan and coordinate events.

The Spending Sub-Committee is responsible for budgeting and planning expenditure of funds, raised by the CSPA, following bids from the School. The Sub-Committee may sanction up to £250 on any one item but larger items are referred to the Executive Committee.

The Fundraising Sub-Committee is responsible for organising events and initiatives to raise funds in response to the School's request for financial support. These requests may be small items such as a toaster for the Coach House Café or major items such as the support of the science status bid.

The Education Sub-Committee is responsible for helping the School identify educational issues of general interest or concern to parents where further information or discussion may be beneficial. This may involve the curriculum, teaching methods, exams, pastoral and disciplinary issues.

As well as input from the committee and sub-committee members the CSPA is reliant on many volunteers to provide both expertise and backup in planning and staging events. The CSPA is only as good as the support given by parents. Outside of the committees parent support is needed in a wide range of areas from talking at a careers convention, to laying tables at fundraising events, to stuffing envelopes for a mail shot. Lists of volunteers are established from forms completed at CSPA events, input to the website or through personal contact with committee members. It is vital to the success of the CSPA that all parents who can provide support ensure that their details are available to the CSPA.