Addressing the climate crisis requires the net zero transition of millions of SMEs globally. SMEs have a significant aggregate environmental footprint and need to adopt cleaner business models. As eco-entrepreneurs and eco-innovators, they also have a key role to play in devising innovative climate solutions. Access to finance is essential for SME investments in net zero, but small businesses face considerable challenges in tapping into the growing pool of sustainable finance. This challenge is likely to grow as financial institutions seek to comply with mandatory environmental reporting requirements. This policy paper examines the sustainable finance landscape for SMEs, the various actors in the ecosystem and the key drivers and barriers affecting the supply of and demand for sustainable finance. It provides an overview of the key policies and instruments in place to support SME access to sustainable finance and identifies considerations for future public support and policy making.