Originating in negotiations for the United Nations Kyoto Protocol, a global carbon market has recently evolved. A number of distinct markets are encompassed within its remit, including a voluntary retail arm. Although the volunatary retail market is very small in comparison to other segments, it has large growth potential as it can extend to countries, customer groups and technologies not embraced by the existing compliance regime. This paper examines the structure and dynamics of the voluntary retail carbon market and in light of these findings considers the future developments and implications of this market for sustainable development.