Ashoka: Innovators for the Public TM was set up 25 yr ago by Bill Drayton, recently voted by the Centre for Public Leadership at Harvard University's John F. Kennedy School of Government in collaboration with US News and World Report among America's 25 Best Leaders. Ashoka coined the term ‘social entrepreneur’. Its first insight was that there was nothing more powerful than a big social idea, but only if it is in the hands of a first-class social entrepreneur. The organisation works as a social venture capital fund, helping selected ‘Fellows’ with start-up funds to launch their ideas. The Fellows’ direct impact is only the beginning; they are role models who inspire others to become active Changemakers. Ashoka weaves them together into a global community whose collaborations are far more powerful than the sum of its solo practitioner parts. This paper examines the evolution of Ashoka, its role as a driver of social change, and the various collaborations and institutions it has helped build and is still in the process of building to promote social entrepreneurship.