The United Nations General Assembly declared 2014-2024 as the International Decade of Sustainable Energy for All (SE4All), following the UN Secretary General’s initiative and emphasizing the importance of energy issues for sustainable development. One of the three objectives of the SE4All initiative is to double the global rate of improvement in energy efficiency by 2030.Improving energy efficiency is supposed to be easy to do and contributes to energy security, a better environment, quality of life, and economic well-being for all. Energy efficiency is called “the first fuel “as it is the best way of getting more out of existing resources, supporting economic growth, and reducing energy costs. Significant potential for improving energy efficiency exists worldwide, but attempts to improve it often fall short because of inadequate national policy frameworks or lack of enforcement of appropriate legislation. Among the drawbacks are policies that artificially lower energy prices and thus encourage wasteful consumption; production and consumption subsidies that distort markets; poorly-managed housing stock; and barriers to entry for new market participants. Despite the multiple benefits, improving energy efficiency remains elusive. The state of the global economy and the economics of energy markets have prioritized short-term economic considerations, and geopolitics has moved energy security to the forefront of policy considerations. To make the first step in overcoming the current inertia, countries need to develop policies and capabilities in the private and public sectors at the local level to identify, formulate and present energy efficiency investment projects that are bankable; introduce policy and institutional changes to support energy efficiency investments; and create favourable conditions for financial institutions and commercial companies to invest in energy efficiency projects. This publication has been prepared in the framework of the United Nations Development Account project “Promoting Energy Efficiency Investments for Climate Change Mitigation and Sustainable Development”, which is implemented jointly by all five UN Regional Commissions, with UNECE being the lead agency. The publication highlights best policy practices for promoting energy efficiency in thence region and beyond. It presents a structured framework of policies and measures to promote energy efficiency investments for climate change mitigation and sustainable development, as well as to develop a menu of energy efficiency policies and measures. Governments, the business community, experts, project developers, and other stakeholders may find this publication to be a useful companion for understanding and applying best policy practices in improving energy efficiency