Energy efficiency is widely recognised as the most cost-effective and readily available means to address numerous energy-related issues, including energy security, the social and economic impacts of high energy prices, and concerns about climate change. At the same time, energy efficiency increases competitiveness and promotes consumer welfare. In this context, it is important to develop and maintain well-founded indicators to better inform policy making and help decision makers formulate policies that are best suited to domestic and/or international objectives. This publication enables energy analysts and policy makers to identify priority areas for the development of energy efficiency indicators, define which sector(s) offer the greatest potential to further improve energy efficiency, select the data and indicators that best support policy development in these sectors, and develop a strategy to advance policy development through the improved use of indicators to track progress of energy efficiency policies.