Industrial and service energy efficiency has become one of the most important strategies for energy transition. Nevertheless, the promotion of energy efficiency in these sectors remains difficult in many cases and requires governmental intervention, policies, and strategies, such as the Learning Energy Efficiency Networks (LEENs) for Energy Management Systems (EMSs), developed in the late 1980s by Switzerland and adopted by several countries.This book discusses the experience with LEENs for EMSs in the industrial and service sectors in Latin America. It highlights the relevance and role of enabling conditions and key stakeholders to gather the main contribution of LEENs; as well as the key challenges. The lessons learned in these Latin American countries can be of great interest to other developing countries, particularly for public policies.