Collaboratives for energy efficiency have a long and successful history and are currently used, in some form, in more than half of the U.S. states. Collaboratives can be useful to gather stakeholder input on changing program budgets and program changes in response to performance or market shifts, as well as to provide continuity while regulators come and go, identify additional energy efficiency opportunities and innovations, assess the role of energy efficiency in new regulatory contexts, and draw on lessons learned and best practices from a diverse group. This guide defines and examines four different types of collaboratives based on their origin, scope, decision-making method, membership, duration, available resources, and how they interact with and influence their respective commissions. The guide also highlights common elements and conclusions on the overall effectiveness of specific characteristics of different types of collaboratives. As comprehensive, sophisticated programs have evolved, so too have the purpose, usefulness, and focus of collaboratives. Increasingly, customers as a group are seen as a vital and strategic, demand-side power sector resource with distinct advantages over other resources. States with energy efficiency collaboratives are likely to find themselves better able to respond to these trends and utilize this resource. This guide provides valuable context for decision makers as they design new or improve existing energy efficiency collaboratives.