This paper seeks to present a theoretical development of the main lines of research that have addressed the emergence of a European Public Sphere (EPS). To this end, the outcomes of the literature are organized into three main categories: political communication in the European Union (EU), the role of digital platforms in a potential public sphere, and the progressive politicization of the EU. Finally, a range of pending challenges are identified. Facing them will help improve research in this field. The increasing politicization of 'Europe' as a topic in the literature and the constant use of digital platforms encourage a European public opinion, which acts together on certain issues beyond the institutional framework. The studies of the coming years have the challenge of combining these variables as well as broadening methodological and theoretical models.