To support partner countries in achieving their Nationally Determined Contributions (NDCs) and pursuing green growth, development co-operation providers will need to better engage with the private sector to mobilise resources, innovation and know-how. This paper contributes to the emerging literature on how development co-operation providers are working with and through the private sector to promote development outcomes. With a focus on green growth and climate change, the paper provides a broad overview of private sector engagement (PSE) approaches used by development co-operation providers, discusses ongoing challenges, and highlights emerging areas of good practice. The challenge is great, as much of the infrastructure investment needs in coming decades will be in emerging and developing countries.