The Mediterranean agro-food systems need to be properly managed. A promising pathway is the transition towards more sustainable food systems through agroecology, which represents the ecology of food systems. In this paper, the state-of-the-art of agroecology is described for three representative euro-Mediterranean countries: Italy, Greece, and Spain. The analysis has been partly based on results of a dedicated literature search and partly on grey literature and expert knowledge. After an overview of the history of agroecology, targeted research and education, collective action (political and social), and some agroecological practices in the three countries are presented. These countries share a rather similar use of the term “agroecology”, but they differ regarding (i) the existence/extent of strong civil and social movements; (ii) the type of study/educational programmes, and the relative importance of different scientific disciplines and their evolution; (iii) the development of political support and legal frameworks; and (iv) the elaboration of concepts to rediscover traditional practices and apply new ones, often taken from the organic agriculture sector. Agroecology is an emerging concept for the Mediterranean agricultural sector, with huge potential due to the peculiar socio-cultural, bio-physical, and political-economic features of the region. To boost agroecology in Mediterranean Europe, better networking and engagement of different actors within a coherent institutional framework supporting the transition is strongly needed.