SummaryThe European Commission recently embraced the concept of agroecology as a pathway to reduce negative impacts from agri‐food systems on the environment. So far, it remains unclear whether agroecology can deliver on these high hopes if implemented on a large scale. We here assess socio‐economic and environmental implications of multiple agroecological futures in the European Union in 2050, based on a novel diagnostic scenario approach, i.e. the biomass balancing model BioBaM‐GHG 2.0. We find that agroecological measures from the plot to the food systems level can indeed reduce environmental pressures while maintaining domestic food availability within the EU. Such measures are, for example, more hedgerows on croplands or reduced biomass harvest on high natural value – HNV grasslands. However, a key prerequisite is an overall reduction of the food system's size (based on the reduction of animal production, food wastes, and export production) and an optimised crop‐livestock integration. Only then does the transformation towards an agroecological agri‐food system in the EU not risk overstretching domestic land availability or produce insufficient agricultural commodities. Mitigating the accompanied trade‐off of reduced farm income is a central mandate for policy development aimed at re‐designing agriculture in Europe to align with the Green Deal goals.