Many cities and municipalities lack the resources to prepare for and respond to threats like extreme weather, economic volatility, and aging infrastructure. Energy systems are particularly vulnerable because of their interactions with other systems that allow communities to function and thrive, e.g., transportation, housing, and business activity. This report discusses ways in which energy efficiency can increase the resilience of energy systems and the communities they serve. It reviews the resilience-related benefits of efficiency measures, discusses the incorporation of efficiency into resilience planning, and presents four case studies showing how local governments and utilities can leverage energy efficiency to increase the resilience of their communities. Although much potential remains untapped, the report finds that energy efficiency is a clear pathway toward making communities and their residents stronger, safer, and more resilient.