The evidence is clear: energy efficiency has played, and continues to play, a large and valuable role in the sustainable development of the global economy. The energy demand that is avoided as a result of steady improvements in the efficiency of energy-using stock such as buildings, cars and appliances is larger than the total final consumption from coal, oil or gas in IEA member countries. The market for energy efficiency investments is very large - estimated between USD 310 billion and USD 360 billion in 2011 - and this market is producing results: total final consumption in IEA countries is estimated to be 60% lower today because of energy efficiency improvements over the last four decades. Since 2001, investments in energy efficiency in 18 IEA countries have helped to avoid over 1 700 million tonnes of oil-equivalent from being consumed. This year's report includes an in-depth look at energy efficiency developments in the transport sector and in finance. Huge new waves of demand for mobility are emerging in OECD non-member economies, bringing with them the challenges of pollution and congestion already faced in OECD countries. Fuel-economy standards and other policies are expected to help shape the market for more energy-efficient vehicles in the years to come. In financial markets, energy efficiency is becoming an important segment in its own right, aided by a growing range of financial products. We document the growing scale and diversity of energy efficiency products and actors. Finally, this report reviews national energy efficiency market developments in various jurisdictions around the world, including Canada, China, the European Union, India and Italy. These case studies provide snapshots of specific energy efficiency sub-markets, and insights into how these markets may evolve in the coming years.