The Environmental Economics for Marine Ecosystem Management Toolkit (in further text: Toolkit) has been developed within the GEF Large Marine Ecosystems Learning Exchange and Resource Network (GEF LME:LEARN) project. GEF LME:LEARN is a GEF-UNDP-IOC/UNESCO project designed to improve global ecosystem-based governance of Large Marine Ecosystems (LMEs) and their coasts by generating knowledge, building capacity, harnessing public and private partners and supporting south-to-south learning and north-to-south learning. A key element of this improved governance is mainstreaming cooperation between LME, Marine Protected Area (MPA), and Integrated Coastal Management (ICM) projects in overlapping areas, both for GEF projects and for non-GEF projects. This full-scale project plans to achieve a multiplier effect using demonstrations of learning tools and toolboxes, to aid practitioners and other key stakeholders, in conducting and learning from GEF projects.