This book constitutes the proceedings of the 6th International Conference on Decision Support Systems Technologies, ICDSST 2020, organised in Zaragoza, Spain, in May 2020. The conference was held online only due to the Corona pandemic. The EWG-DSS series of International Conference on Decision Support System Technology (ICDSST) is planned to consolidate the tradition of annual events organized by the EWG-DSS in offering a platform for European and international DSS communities, comprising the academic and industrial sectors, to present state-of-the-art DSS research and developments, to discuss current challenges that surround decision-making processes, to exchange ideas about realistic and innovative solutions, and to co-develop potential business opportunities. The main topic of this year’s conference was “Cognitive Decision Support Systems and Technologies”. The 13 papers presented in this volume were carefully reviewed and selected from 51 submissions. Theywere organized in topical sections named: methodological contributions; case studies and applications; and overview (on the current state and future trends of DSS, BI, and data analytics research).