Dr Alex Nicholls (Skoll Centre for Social Entrepreneurship) examines how over the past ten years the market for Fair Trade products has grown at double digit rates across many countries in the North. As a consequence, Fair Trade is today the most significant example of a social enterprise entering mainstream markets. Furthermore, the Fair Trade model has had an influence beyond its own particular markets by playing an important role both specifically in establishing the 'ethical consumer' as a viable market segment and in exposing exploitation across mainstream supply chains to the public more generally. Fair Trade has its roots in a range of social movements that campaigned for trade justice, often within a strong religious (Christian) framework. This paper explores the micro-process through which Fair Trade has been transformed from a social movement focussing on advocacy against mainstream corporations to a market-embedded model of ethical consumption often working in cooperation with mainstream retailers and wholesale brands. It suggests that the development of Fair Trade certification standard and its attendant label provided the boundary spanning mechanism by which mainstreaming was facilitated. However, it is also proposed that this process, and its ongoing development, present challenges for Fair Trade as a movement that may have serious future implications. Creative Commons Attribution-Non-Commercial-Share Alike 2.0 UK: England & Wales; http://creativecommons.org/licenses/by-nc-sa/2.0/uk/