The external dimension of EU energy law is gaining momentum in legal scholarship. The European Union has reached a certain degree of influence in exporting its internal energy rules and values beyond the Member States. Nevertheless, the theory of legal harmonisation between the EU and 'third countries' remains underdeveloped. This paper aims to address this deficit by analysing the effects of legal harmonisation in energy outside the current domain of the EU. The paper draws on the example of Georgia, as a Contracting Party to the Energy Community Treaty, and assesses the potential impact of EU energy legislation on Georgia's municipal law triggered by the Community membership. It further uncovers a number of uncertainties that are likely to arise before Georgia in the course of implementing the energy acquis and advocates for the process to be guided through a set of common energy law principles. These aspects are discussed to explain the nature of expanding EU energy law and policy in 'third countries' and to contribute to the ongoing debate about energy law, as an emerging academic discipline.