Achieving sustainability in fisheries remains a challenge for most countries around the world. The growth in eco-labelling in the fisheries and seafood sector that had started in the 1990s continued after that, to the extent that by 2012, producers, processors, retailers and others in the seafood industry were complaining about the confusion they were experiencing with the number of eco-labelling schemes that had been established and the difficulties they were experiencing in being able to identify which of these schemes were credible. Many stakeholders in the seafood industry agreed to establish an organization, the Global Sustainable Seafood Initiative (GSSI) to 'provide clarity on seafood certification and ensure consumer confidence in certified seafood'. This chapter discusses the role and impact of the GSSI. The FAO guidelines specify a set of 'minimum substantive requirements' that an eco-labelling scheme should require a fishery to meet in order to qualify for certification and labelling.