This Scientific Summary on Multiple Ocean Stressors for Policy Makers offers a reference for all concerned stakeholders to understand and discuss all types of ocean stressors. This document will help coordinate action to better understand how multiple stressors interact and how the cumulative pressures they cause can be tackled and managed. It is a first step towards increased socio-ecological resilience to multiple ocean stressors (Figure 1). Ecosystem-Based Management (EBM)1 recognizes the complex and interconnected nature of ecosystems, and the integral role of humans in these ecosystems. EBM integrates ecological, social and governmental principles. It considers the tradeoffs and interactions between ocean stakeholders (e.g. fishing, shipping, energy extraction) and their goals, while addressing the reduction of conflicts and the negative cumulative impacts of human activities on ecosystem resilience and sustainability. Thus, EBM is an ideal science-based approach for managing the impacts of cumulative stressors on marine ecosystems. The United Nations Decade of Ocean Science for Sustainable Development (2021–2030; Ocean Decade), which is based on a multi-stakeholder consultative process, identified 10 Ocean Decade Challenges. Challenge 2: Understand the effects of multiple stressors on ocean ecosystems, and develop solutions to monitor, protect, manage and restore ecosystems and their biodiversity under changing environmental, social and climate conditions addresses the overall outcomes of the Decade. In particular, outcomes aimed at a clean, healthy and resilient, safe and predicted, sustainably harvested and productive, and accessible ocean, with open and equitable access to data, information and technology and innovation by 2030. This Scientific Summary for Policy Makers is also a call to action underlining the urgency to understand, model and manage multiple ocean stressors now. We cannot manage what we do not understand, and we cannot be efficient without prioritization of ocean actions appropriate to the place and time.