Sustainable development aspires to “leave no one behind”1. Even so, limited attention has been paid to small-scale fisheries (SSF) and their importance in eradicating poverty, hunger and malnutrition. Through a collaborative and multidimensional data-driven approach, we have estimated that SSF provide at least 40% (37.3 million tonnes) of global fisheries catches and 2.3 billion people with, on average, 20% of their dietary intake across six key micronutrients essential for human health. Globally, the livelihood of 1 in every 12 people, nearly half of them women, depends at least partly on small-scale fishing, in total generating 44% (US$77.2 billion) of the economic value of all fisheries landed. Regionally, Asian SSF provide fish, support livelihoods and supply nutrition to the largest number of people. Relative to the total capture of the fisheries sector (comprising large-scale and small-scale fisheries), across all regions, African SSF supply the most catch and nutrition, and SSF in Oceania improve the most livelihoods. Maintaining and increasing these multidimensional SSF contributions to sustainable development requires targeted and effective actions, especially increasing the engagement of fisherfolk in shared management and governance. Without management and governance focused on the multidimensional contributions of SSF, the marginalization of millions of fishers and fishworkers will worsen.