This OECD report provides comprehensive assessment of blended finance – mixing different forms of capital to support development – as a solution for mobilizing resources toward the SDGs in developing countries. Published in 2018, it examines actors, instruments, lessons learned, and risks of scaling up blended finance. The report argues that while blending has potential to scale commercial finance for SDGs, deployment needs common framing, principles, and evidence-based analysis. It includes case studies, surveys, and recommendations for policy makers and practitioners working on sustainable development financing.