Today the OECD launched the Development Co-operation Report 2018: Joining Forces to Leave No One Behind. The SDSN secretariat contributed to this report and drafted the full chapter 4 on “Delivering the Sustainable Development Goals for all: Policy priorities for leaving no one behind.” Drawing on successful examples, this chapter explores how to meet three challenges to SDG achievement: investment, policy and data. Sections discuss financing for leaving no one behind, how to coordinate planning and budgetary processes to make more efficient use of resources, how to encourage long-term, cross-sectoral planning and build the necessary data systems to enable targeted, and effective interventions. The chapter then uses a good practice example from the MDG period (2000-15) focused on the health sector, where access to treatments for malaria, AIDS, and tuberculosis improved significantly, including for the most vulnerable population groups in low-income countries, to illustrate how investment, policy and data challenges can be met in the context of the SDGs. In particular, it discusses the role that development cooperation can play in generating and scaling up innovations to improve health, education, and other societal outcomes.