This paper examines different forms of innovation including social innovation, and why innovation and social innovation have become important themes in public policy in a context of the increasing and diverse demands on welfare regimes, and in an era of constrained budgets. It will review different perspectives on innovation and social innovation and the dynamic interaction through collective entrepreneurship in the the social and solidarity economy; bringing out process and outcome dimensions of innovation. And it will develop an understanding of the drivers and barriers to innovation, including the role of the institutional and policy framework. It will set this analysis within the context of public policy, demonstrating the role of public policy in enabling such innovations in the social and solidarity economy.