The social financeSocial finance ecosystem is a network of organizations, actors, and systems that mobilize capital for investmentsInvestment that create financial returns and social and environmental value. This ecosystem includes investors, social enterprises, intermediaries, banks, and policymakers, all of whom are co-creating solutions for global issues ranging from poverty and inequality to climate change and access to healthcare. This chapter provides an overview of the ecosystem’s components, how they interact, and how they come together to support sustainable development and social change. It discusses the role of investors who fund impact-oriented projects, social enterprises that combine business and social purpose, intermediaries who facilitate exchanges and hold actors accountable, and policymakers who establish regulation and incentives. By emphasizing the relationship and purpose of these components, the chapter exhibits how social finance promotes innovation, transparency, and scalable solutions for critical social problems.