<div>This book constitutes the refereed proceedings of the 11th International Symposium on Foundations of Information and Knowledge Systems, FoIKS&nbsp;2020, held in Dortmund, Germany, in February 2020.</div><div><br></div><div>The 19 revised full papers presented were carefully reviewed and selected from 33 submissions. The papers&nbsp;address various topics such as big data; database design; dynamics of information; information fusion; integrity and constraint management;&nbsp;intelligent agents; knowledge discovery and information retrieval; knowledge representation, reasoning and planning; logics in databases and&nbsp;AI; mathematical foundations; security in information and knowledge systems; semi-structured data and XML; social computing; the semantic&nbsp;web and knowledge management; and the world wide web.​</div>