The way electricity is generated and consumed in the US is quickly changing, including in terms of the rapid growth in variable power generation resources and the need for large-scale investments to replace aging infrastructure and modernize the grid. Buildings that coordinate electricity use with grid conditions are a flexible and cost-effective resource to address the evolving power system challenges. Outfitted with smart technologies, grid-interactive efficiency buildings (GEBs) are energy-efficient buildings with smart technologies characterized by the active use of distributed energy resources to optimize energy use for grid services, occupant needs and preferences, and cost reductions in a continuous and integrated way. In doing so, GEBs can play a key role in promoting greater affordability, resilience, environmental performance, and reliability. The Roadmap – which was developed by a team led by Lawrence Berkeley National Laboratory and The Brattle Group in collaboration with the US Department of Energy (DOE) Building Technologies Office – identifies the most important barriers and outlines the key opportunities for full implementation of GEBs and associated demand flexibility.