This report provides insights on the political economy of biodiversity related policy reforms. It draws on existing literature and four new case studies covering the French tax on pesticides, agricultural subsidy reform in Switzerland, EU payments to Mauritania and Guinea-Bissau to finance marine protected areas via conservation trust funds, and individually transferable quotas for fisheries in Iceland. Each case study focusses on the drivers of reform, the types of obstacles encountered, key features of the policy reform, and the lessons learned from the reform experience.