This book constitutes the refereed proceedings of the 16th International Conference on Flexible Query Answering Systems, FQAS 2025, held in Burgas, Bulgaria, during September 11&13, 2025.The 26 full papers presented were carefully reviewed and selected from 49 submissions. The proceedings also include 3 invited talk and 2 tutorial papers. They were organized in the following topical sections: Invited Talks; Flexible Query Answering Systems; Data-driven Quality Management and Intelligent Systems for Academic Processes and Flexible Decision-making; Language Models in Advanced Information Retrieval; Intuitionistic Fuzzy Approaches for Flexible Querying and Reasoning under Uncertainty; and Emerging Trends in Flexible Query Answering and Information Retrieval.