The 2030 Agenda for Sustainable Development defines international trade as "an engine for inclusive economic growth and poverty reduction, [that] contributes to the promotion of sustainable development". In order to become a 'sustainable engine' one approach that seems to be increasingly used is to internalize social, economic and environmental concerns in international trade. This can be done by many different means and policy instruments and tools. In this report we focus on a specific tool, namely Voluntary Sustainability Standards (VSS) which comprise of certification schemes, labeling programs and private standards. VSS aim to make global value chains - from producer to consumer - more sustainable, taking into account social and environmental requirements in the production process. VSS also often link developing countries (where many producers are based) to developed countries.