This research report presents a framework designed to assess gambling-related harms in Great Britain. The framework uses a public health approach to take into account the broad impacts of gambling. Measurement tools are introduced that can be used to assess the extent of gambling-related harm as well as the recovery process, including the Gambling Harm Severity Index (GHSI) for people who gamble and affected others. The GHSI is linked with quality of life indicators so that gambling harm can be tracked alongside other other public health issues. Policy makers and practitioners can use the framework and tools to design targeted interventions, monitor outcomes, and evaluate the effectiveness of harm reduction strategies.