This 4th Flagship Report by the UNFSS aims to provide an understanding of the role of government as a vehicle to drive the adoption of voluntary sustainability standards (VSS). The effectiveness of VSS to contribute to sustainable development partly depends on their degree of adoption by economic operators. In this respect, governments can play a significant role through public procurement and trade policy. The integration of VSS into public procurement and trade policies is potentially a powerful means to upscale their adoption. Public procurement represents, on average, 12 per cent of gross domestic product (GDP) in countries of the Organisation for Economic Co-operation and Development (OECD), and up to 30 per cent of GDP in developing countries. Given the magnitude of such spending, in combination with the pressing need for sustainable production and consumption, sustainable public procurement (SPP) has become imperative. In addition, trade policy is increasingly being used to pursue non-trade objectives, including those relating to sustainability. This report seeks to answer the following key questions: • What are the determinants of VSS adoption at country level? • How can public procurement and trade policy serve to increase VSS uptake, and how do they contribute to the effectiveness of VSS? • What are the key considerations and implications of VSS integration into SPP and trade policy?