This special issue is based on the program area “Decision support” of the EURO 2021 conference held online and on-site in Athens, Greece, on July 11–14, 2021. It contains papers presented at the conference and later submitted for this special issue, as well as additional papers submitted in response to an open call for papers after the conference. More than 30 papers were submitted for this special issue and were processed following the regular review procedures of ITOR thanks to a large international committee. Finally, we were able to accept the 14 papers collected in this special issue. This special issue focuses on the new possibilities that recent developments in information technology and algorithms offer for decision support. The papers collected in this special issue give a comprehensive overview of different areas in which the availability of rich data improved processing capabilities and algorithms, and the possibility to connect and involve a large number of stakeholders and users in decision processes have changed and enhanced the possibilities of decision support.