The main aim of this chapter is to investigate the renewable energy strategies and sustainability challenges in the Western Balkan countries. The key sustainability challenges are to achieve energy efficiency and to produce clean energy from renewable resources. Although most of the research included developed countries, there is a growing interest in studying renewable energy in developing economies. The methodology approach involves an extensive literature review, comparative analysis of national and European Union policy documents, and empirical data regarding energy production and consumption, as well as the adoption of renewable energy. The findings revealed that the region has great potential in renewable energy resources, but exploration obstacles remain. The region has embraced the Western Balkans 6 as a basis for expedited sustainable growth across all the countries in the region. The investment opportunities will be discussed, too.