This document is the 2012 International Energy Efficiency Scorecard report published by the American Council for an Energy-Efficient Economy (ACEEE). The report analyzes and scores 12 major economies on their energy efficiency across national efforts, buildings, industry and transportation. It finds that the top-scoring countries demonstrate solid performance across all sectors, while no country achieves a perfect score and all have room for improvement. The United States scores relatively low overall due to weaknesses in national efforts, buildings and transportation. The report makes recommendations for how countries can advance energy efficiency to boost economic competitiveness.