In Europe, developing Agroecology requires a redesign of production systems towards agroecology, to provide a scope of environmental, economic and social benefits at local and global level. We studied the combination of resources that farmers or groups of stakeholders mobilize for developing agroecological farming systems integrated in sustainable food systems, focusing in particular on the resources brought by collective dynamics. We identified fifteen case studies across Europe, selected in various environmental and social contexts and covering the main productions, and studied their functioning and performances. Three case studies are detailed in Denmark, Portugal and Belgium. They all face sustainability challenges such as soil fertility management, biodiversity conservation, and necessity to increase the added-value of their products to remain economically viable. From the case studies, we conclude that agroecological farming systems are diverse and can provide altogether sufficient production levels, acceptable farm viability, and positive impacts on biodiversity ranging from low to very high while guaranteeing accessible, more or less expensive but healthier products for the consumer. Collective action and mobilization of supporting stakeholders (scientists, consumers and local authorities) appear to be determinant for the development of these systems. The most promising case studies rely on adequate combinations of material, cognitive, technical and socioeconomic resources. Enhancing these resources at local and regional level through adequate development policies and stakeholders' mobilization can strongly support the development of agroecology.