This book constitutes the proceedings of the 28th International Symposium on Methodologies for Intelligent Systems, ISMIS 2026, held in Lyon, France, during July 22–24, 2026.

The 19 full papers and 5 industrial papers presented in this volume were carefully reviewed and selected from 44 submissions. The papers are organized in the following topical sections: Invited talks; Knowledge Representation and Formal Reasoning;Generative and Representation Learning; Reliability, Safety and Explainable AI; Industry Session; and Time Series and Stream Data.