Do deep-sea minerals have a place in supply chains as we move towards responsible sourcing of materials? Demand for these minerals, such as cobalt and nickel, is forecasted to dramatically increase. But mining would damage seafloor ecology, leading to wider environmental and social effects. This report identifies significant gaps in knowledge, stakeholder participation and consensus that impede sound decision-making on deep-sea mineral stewardship. It calls for decision-making to be improved through urgently closing knowledge gaps on potential impacts, consensus-building and increased stakeholder participation. We owe it to future generations to be precautionary and well-informed stewards of our common natural heritage.