The 22nd European Agent Systems Summer School (EASSS 2021) is organized by the Artificial Intelligence and Computer Science Lab of the University of Porto (LIACC), and held online, on July 19-23, 2021. EASSS 2021 is organized under the auspices of the European Association for Multi-Agent Systems (EURAMAS) and the Portuguese Association for Artificial Intelligence (APPIA), as an Advanced School on Artificial Intelligence.