Energy Service Companies (ESCOs) and Energy Performance Contracting (EPC) are seen as private-sector delivery mechanisms for energy efficiency, and understanding ESCO market developments, its limitations, and the success of relevant policies and programmes is helpful for policy-makers. This article presents a comprehensive overview of the ESCO industry in EU Member States and neighbouring countries based on a large-scale expert survey, focused on market development between 2010 and 2013. Drivers and barriers are analysed, recommendations on additional measures to further promote the national and EU ESCO markets are suggested. The previously characteristic growing trend continued, and most of the markets were getting stronger during the period. Germany, France, Austria, the Czech Republic and the UK were the most active markets in 2013, and only Cyprus, Estonia and Malta remain without ESCO activity. The size of the EU market was estimated at (sic)2.4 billion in ESCO revenue in 2015. ESCO markets were found to be driven as much by market forces (i.e. increasing energy costs, growing awareness, development of partnerships), as by dedicated policy measures, regulations and financial solutions. Interestingly the list of drivers is similar in many countries, but the leveraging success factors and the leading barriers are diverse.