The UN Sustainable Energy for All initiative aims to double the global rate of improvement in energy efficiency by 2030.i Efficient buildings are vital to achieving sustainable development because they align economic, social, and environmental objectives, creating triple bottom line benefits. However, the scale and pace of current actions around the world are insufficient to transform buildings into engines of the sustainable, energy efficient economy. This second-edition report reviews government policy options that can accelerate building energy efficiency improvements. New in this edition is a building efficiency policy assessment tool that provides a practical starting point for accelerating energy efficiency policy development. The tool offers a simple framework to help decision-makers set policy priorities with input from stakeholders. It outlines a workshop designed to support consensus-based, multi-stakeholder collaboration and uses visual tools to build consensus and prioritize building efficiency policy options and strategies. This edition also includes new content on the private-sector’s role and priorities around building energy efficiency, in particular describing how to create market conditions that support investment in energy efficient buildings and leverage private-sector capital, technology and services to scale up the market.