Countries in the Gulf Cooperation Council (GCC) region are facing many challenges due to climate change’s effects on already-scarce water supplies. Energy resources and the energy sector are heavily tied to the water sector as desalination and other provision capacities are fueled by oil. This World Bank report, "Advancing Knowledge of the Water-Energy Nexus in the GCC Countries" focuses on these challenges and what opportunities there are for GCC countries to better manage their water and energy sectors. The report highlights potential pathways for improvement, such as addressing subsidies and pricing to discourage waste, increasing re-use of treated wastewater, and scaling up renewable energy use. Building on innovations already underway in the region, the report showcases a real opportunity to make changes in the sector for more efficient use of water and energy, which in turn promises to have positive effects on climate, jobs, and fiscal sustainability.