This chapter discusses the importance of the legal aspects of energy policy. It advances two main propositions: (a) different legal expressions of similar energy policies have different implications for the effectiveness and overall impact of a policy, and (b) the choice of legal expression is highly constrained by (i) law as a technology (i.e., the tools available to translate a policy into legal terms), (ii) the need to fit the policy within a broader legal framework and (iii) the underlying economic, social and political considerations affecting the choice of certain legal expressions. The chapter illustrates these two propositions by reference to three case studies relating to the extraction of shale gas in the EU, decarbonisation in the United States, and state support for renewable energy in India.