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 ranks 12 major economies based on their energy efficiency across national efforts, buildings, industry and transportation using 27 metrics. The United Kingdom scored the highest overall with 67 out of 100 possible points. The report finds that while some countries are outperforming others, all countries have opportunities to improve energy efficiency. It then focuses specifically on historical trends and recommendations to improve energy efficiency in the United States.