Dunoon Grammar School has a very long and distinguished history spanning over 350 years of growth, of which high standards of academic and personal development have been the hallmarks. Dunoon Grammar School gained its royal charter in 1641.

Dunoon Grammar School is a six year co-educational, non-denominational comprehensive school with a roll of over 1000 pupils (the school can accommodate 1150 pupils).

The school provides extensive computer provision throughout and consists of two main teaching blocks with two gymnasia, a games hall and an assembly hall. In the main building there is a suite of rooms, purpose built for education of pupils with additional support needs. There is, in addition, a technical block, music rooms, and two all weather pitches serviced by training floodlights which can be used for both hockey and football. All the facilities of the building are available for community purposes and letting can be arranged through the Area Community Education Officer.

Dunnoon Grammar School has eleven associated primary schools: Dunoon, Innellan, Kilmodan, Kirn, Lochgoilhead, St. Mun's, Sandbank, Strachur, Strone, Tighnabruaich and Toward. Distance travellers to the school are accommodated in the school hostel in Hunter Street, Kirn.