The Climate Pact and the European Green Deal constitute the main components of the European Union (EU)’s climate change policy. Energy transition, that is, transformation to a zero-carbon global energy system, is one of the main pillars of climate change mitigation policies. This transformation, coupled with the empowerment of individuals within the energy system, shifts citizens from their roles as customers towards a more active role. Within this framework, energy communities stand out as significant facilitators for the participation of individuals and communities in the energy system, promoting self-consumption and contributing to the social acceptance of renewable energy initiatives, among other direct and indirect benefits. The main directives introducing energy communities into the EU legal system are RED II and ED 2019. This study, conducted as a part of a Horizon 2020-funded eCREW project, assessed the adaptability and implementability of these two directives within national legislation, along with the associated legal and administrative frameworks, utilizing evidence from Austria, Germany, Greece, Italy, Spain, and Turkey. The comparative analysis also enhances the understanding of the concept of renewable energy communities and citizen energy communities, both in the EU and in nonmember countries. The results of the analysis revealed that none of the countries studied had yet completed the process of harmonizing their legislation concerning energy communities.