This paper develops a new systematic classification and explanation of barriers and drivers to energy efficiency. Using an actor oriented approach, the paper tries to identify (i) the drivers and barriers that affect the success or failure of energy efficiency investments and (ii) the institutions that are responsible for the emergence of these barriers and drivers. This taxonomy aims to synthesise ideas from three broad perspectives, viz., micro (project/end user), meso (organization), and macro (state, market, civil society). The paper develops a systematic framework by looking at the issues from the perspective of different actors. This not only aids the understanding of barriers and drivers; it also provides scope for appropriate policy interventions. This focus will help policy-makers evaluate to what extent future interventions may be warranted and how one can judge the success of particular interventions.