This book constitutes the proceedings of the 14th International Symposium on Foundations of Information and Knowledge Systems, FoIKS 2026, which took place in Hanover, Germany, during March 2026. The 13 full papers and 5 short papers included in these proceedings, together with 7 poster papers, were carefully reviewed and selected from 37 submissions. The papers were organized into topical sections as follows: Team Semantics, Structures for Argumentation and Modal Logics, Belief Bases and Revision, Database Theory, Foundations, Explanations, and Poster Papers.