The chapter aims to conceptualize social entrepreneurship, together with its contribution to social value creation and its relation to innovation and sustainability. The chapter begins by theorizing about social entrepreneurship and the desirable characteristics of a social entrepreneur. Comparisons between the different schools of taught, namely The Social Enterprise School and the Social Innovation School are made in order to understand trends and similarities that might affect the development of a social entrepreneurial ecosystem. Finally, the links between social entrepreneurship, sustainability and social innovation are explored, as well as issues and challenges that might occur in relation to funding strategies, tax and legal regulations, public investment, public awareness and impact measurement. The article concludes that social entrepreneurship contributes to tackling social problems in an innovative manner, bringing together different actors such as government, private companies and social entrepreneurs.