More than a decade of ambitious sector reform has led to a period of stability in the Armenian energy sector. The sector faces challenges more typical of a developed economy than an emerging one: policymakers' concerns have shifted from avoiding total system collapse to optimizing the energy supply mix to provide affordable, reliable, and sustainable energy services. However, some old challenges remain and new ones have arisen. Armenia is still vulnerable to energy supply disruptions; tariffs lag the full cost of service provision; and a significant investment backlog impedes progress in energy infrastructure. The purpose of this note is to present the analysis of the challenges facing Armenia's energy sector, specifically, its electricity, natural gas, and heating subsectors. The intention of the note is not to prescribe solutions, but to present analysis of options and tradeoffs that the Government can use to inform its decision-making. Armenia's energy sector has undergone a series of reforms over the last fifteen years, which included privatization of the electricity distribution and gas companies, and some generating companies, establishment of an independent regulator, and development of a formal strategic plan for the sector. This energy sector overview highlights important outcomes from reforms and describes key sector characteristics.