The Great Barrier Reef is facing unprecedented pressures, and supporting the resilience of the Reef has become a central focus in its management. A key challenge for managers is to understand the cumulative impacts of multiple stressors and incorporating this knowledge into management decisions. The Cumulative Impact and Structured Decision-Making (CISDM) framework represented in this report is designed to assist Great Barrier Reef Marine Park managers and stakeholders in this challenge. The framework uses qualitative and probabilistic modeling to provide a systems-level understanding of how cumulative stressors affect coral reefs and seagrass ecosystems in the GBRWHA. These ecosystems underpin matters of national environmental significance (MNES), including the outstanding universal value (OUV) of the GBRWHA. The modeling approach enables managers to identify precautionary spatial and temporal boundaries for the assessment of development proposals. These ‘Zones of Influence’ are integrated with a structured decision-making process that is designed to help managers and stakeholders use the results of the models to make informed choices between a range of possible intervention scenarios to achieve management objectives.