The concept of social innovation has gained prominence in the international policy making community throughout the last ten years, particularly in the European Union. It is highly ambiguous, with blurring boundaries, involving diverse policy fields and actors in the public, private and non-profit sectors. The articles in this special issue deal with social innovation in a territorial development perspective. With a focus on social policy, they tackle the question of the potential of social innovations to respond to limitations of welfare regimes and they also reflect on the contradictions regarding the combination of social innovation with neoliberal reforms.