Consumers have started to realise that their purchasing behaviour can cause a huge impact to the environment as there is a worldwide concern on environmental degradation issues such as global warming and pollution. ‘Green’ is now in the mainstream of modern businesses. Therefore, being socially responsible by offering green (environmentally friendly) products and services should be the practise of any company that wishes to sustain a competitive advantage in today’s business world. This study was carried out to investigate the relationship between demographic characteristics and green purchase behaviour of Penang’s green volunteers who participate in environmental related activities. The results indicate that females have higher green purchase behaviour compared to males, and as for education level, those with degree and above qualification have higher green purchase behaviour as compared to those with diploma and lower education level. For income as the income level increases the green purchase behaviour of green volunteers is higher. Implication for marketers is further elaborated.