Energy sector is a very crucial sector for a country as it drives economic development, specific policies and diplomatic moves and it is constantly drawing attention. This thesis is a study of energy security and energy threats of the countries of the Eastern Mediterranean, by analyzing factors related to policy, diplomacy, geopolitics, economics and total energy supply. The thesis begins with the state of the art of the literature review of the concept of energy security, and more specifically the definitions of the energy security, its dimensions and its threats are presented. Since there is no global agreement among the academics on a specific definition of energy security, it would be more important to focus on the dimensions of the energy security, because these include many different aspect of this issue. Following the literature review, the countries of the region are presented, which are Greece, Cyprus, Turkey, Lebanon, Israel, Egypt and Libya, with the focus on their energy mix, which proves the importer status of the countries, since these countries depend on energy imports to cover their domestic demand. Moreover, the latest developments in energy, such as the gas discoveries or the possibility of constructing the EastMed pipeline create a new landscape in the region. These give an increasing interest, because of the geopolitical importance of the region. However, there are threats posed to energy security of the countries under study, mainly of political, diplomatic, economic and technical nature.