The Energy Union Communication expected in February 2015 provides the opportunity to bring together the leading dimensions of European energy policy to drive the transition to an integrated, secure, competitive, and sustainable energy sector. To meet these goals, it is essential to reframe the role that efficiency — including energy efficiency and demand response — plays in how Europe plans for, finances, and constructs its energy system. European and international experience show that efficiency delivers multiple benefits to the energy system, consumers, and the economy — often at lower cost than supply-side resources. However, Europe is still not investing enough in its efficiency potential. Achieving this potential requires a high-level commitment to systematically identify the multiple decision points where efficiency is overlooked or undervalued, and put in place concrete policies and measures to ensure that investments happen wherever efficiency is more cost-effective or valuable than equivalent supply-side resources. This approach is called “Efficiency First.” This policy brief identifies several key areas, where applying Efficiency First can result in more cost-effective, competitive choices for Europe.