The group was formed in 1967, when the late Jane Prout and Harry Pye, amongst others, persuaded forward-looking local painters in and around Totnes, S. Devon, to exhibit together. In order to maintain excellence and professional standards the group limited its membership to a maximum of twenty-one artists. To this day it maintains that guiding principle.

At the outset the primary aim was to encourage adventure and experiment, continuing an ethos already well-established by teaching at the Dartington College of Arts. Early guidelines laid down the intention for at least one exhibition a year, showing work new to the town that demonstrated the highest of standards, irrespective of any commercial consideration. Aesthetic values were paramount.

Fifty-seven years on, the 21 Group is one of the longer established exhibiting groups in the South West. Evolving from its close ties with Dartington in those formative years its members are now drawn from a wide area stretching from beyond Exeter in the east, to Cornwall in the west, and northwards towards Okehampton.