This two-volume set LNCS16258-16259 constitutes the refereed proceedings of the 22nd European Conference on Multi-Agent Systems, EUMAS 2025, held in Bucharest, Romania, during September 3–5, 2025.The 33 full papers, 9 short papers, 3 demonstrators and 1 Agent Toolkits community report included in this book were carefully reviewed and selected from 60 submissions. They were organized into the following topical sections:Part I: Engineering Multi-Agent Systems; Agent-Based Modeling and Simulation; Human-Agent Interaction; and Agent Toolkits Community Report.Part II: Formal approaches, Networks and Learning; Short Papers; and Demonstrators.