This thesis aims at analyzing the developments in the EU electricity market over the period 2000 – 2016, by implementing Social Networking Analysis. This period is characterized by significant changes, such as huge penetration of Renewable Energy Sources (RES) in the energy sector, intensification of the efforts to address the climate change and the continuation of the procedure of the liberalization and interconnection of the electricity market at European level. The thesis starts by describing the European energy strategy, presenting its three pillars: competitiveness, security of energy supply and sustainability. Particular emphasis is given to the procedure of the intergration of individual electricity markets. The purpose of a unified market is to contribute to the following issues: the competitiveness of the markets, the stabilization of electricity prices, improvement of energy efficiency and the confrontation of climate change. The electricity market’s liberalization affects the competition among producers and supplies, but also the prices of wholesale and retail trade was based on the EU directives which are listed. The Social Network Analysis is a popular method for analyzing different types of networks, however its implemention of the electricity market transformation is limited. By considering the European electricity market as a network and the regional markets as subnets, the Social Network Analysis enables the examination firstly of the degree of interconnection between the countries, both at regional and European level, and secondly of the role of each country into the energy grid. The countries that are are studied are the 27 EU – countries, with the exception of Cyprus, which is the only one EU member state, that is not interconnected with the rest of the EU network, and therefore the flows from and to the country are zero. Through this study, conclusions can be drawn for the entire EU, for each country separately, as well as on how the network is changing over the years. The thesis provides a clear insight that the countries which have high considerable flows within the European energy network of the EU contribute to its transformation.. However, apart from the EU Member States, the non – EU countries are heavily involved in shaping the European electricity network, confirming the high dependence of the EU from these countries. Alongside, the study highlights the countries that operate as connecting links between isolated states and the rest of the EU network. Finally, it is confirmed that the geografic location of a country plays an important role in the interconnection and the energy transactions which take place.