This book constitutes the refereed proceedings of the 13th International Conference on Flexible Query Answering Systems, FQAS 2019, held in Amantea, Italy, in July 2019.

The 27 full papers and 10 short papers presented were carefully reviewed and selected from 43 submissions. The papers present emerging research trends with a special focus on flexible querying and analytics for smart cities and smart societies in the age of big data. They are organized in the following topical sections:

Flexible database management and querying

Ontologies and knowledge bases

Social networks and social media

Argumentation-based query answering

Data mining and knowledge discovery

Advanced flexible query answering methodologies and techniques

Flexible query answering methods and techniques

Flexible intelligent information-oriented and network-oriented approaches

Big data veracity and soft computing

Flexibility in tools

Systems and miscellanea