Small-scale fisheries (SSF) employ over 90 percent of fishers and fish workers worldwide and, among these, 96 percent live in developing countries where they produce almost as much fish for direct domestic consumption as large-scale fisheries. Despite these contributions, SSF do not receive enough attention in policy. Furthermore, big questions remain: what is the importance of SSF for food and nutrition security, local economies and poverty eradication? How are the overall benefits generated by SSF distributed and how can they be enhanced? What are the key drivers of change in these sectors, including both threats and opportunities? The Illuminating Hidden Harvests Project (IHH), a partnership between the Food and Agriculture Organization, WorldFish, and Duke University, aims to of capture and quantify the contributions of SSF to the three pillars of sustainable development (economic, social and environmental) at local and global levels. Using a diversity of methods, including case studies, global datasets, and thematic studies, this will allow the quantification of key indicators on a global scale and will highlight local examples where a global synthesis is perhaps not yet possible. This will also underpin a more informed inclusion of SSF in the international policy-making process. In addition, the results of IHH will support the design of a participatory framework for the implementation and monitoring of the Voluntary Guidelines for Securing Sustainable Small-Scale Fisheries in the Context of Food Security and Poverty Eradication (SSF Guidelines) around the world. By highlight the role that SSFs play in achieving the Sustainable Development Goals (SDGs), in particular SDG 1 (no poverty) and SDG 2 (food security), the IHH research aims to increase the support from policy-makers for the implementation of the SSF Guidelines.