<p>Renewable Energy Communities (RECs) represent an important resource for promoting the energy transition through participative forms of governance. Focusing on communicative processes is crucial for the success of RECs, since effective communication can promote citizens’ engagement and participation in these projects. This systematic review aims to investigate communication within the RECs, exploring the main communicative strategies and channels, as well as the main actors involved in communicative processes. Following the PRISMA guidelines, we screened two databases (Scopus; Web of Science), analyzed the resulting sample (<i>n</i> = 886 records), and selected 9 papers that met the eligibility criteria. The findings emphasize the importance of a clear and transparent communication style that is understandable to all community members, and the critical role of local leaders in promoting community engagement by acting as a bridge between community members, institutions, and experts. RECs’ communicative processes differ depending on the target audience and the project’s development stage, implying the need for a deep investigation of phases and peculiarities to design successful communication strategies. This paper provides a systematic overview of the current state of RECs’ communicative processes in research, highlighting an important gap in the current literature. Further research should be conducted on this topic, focusing on how RECs should adjust communication depending on community features and project stages, what channels and contents are particularly effective, how practices of RECs are narrated within their communities, and how these narratives can strengthen citizens’ participation.</p>