This book constitutes the contributions presented at the RCIS 2026 Forum and Doctoral Consortium, held in conjunction with the 20th International Conference on Research Challenges in Information Science, RCIS 2026, which took place in Toulouse, France, during May 2026. The scope of RCIS is summarized by the thematic areas of information systems and their engineering; user-oriented approaches; data and information management; business process management; domain-specific information systems engineering; data science; information infrastructures; and reflective research and practice.The conference received 8 submissions to the Forum, 11 submissions to the Doctoral Consortium, and 116 submissions to the main track. For the RCIS 2026 Forum, a total of 14 papers were accepted (5 from 8 direct submissions to the Forum, and 9 from the submissions to the main track). And for the Doctoral Consortium, 8 papers have been included in these proceedings from a total of 11 submissions.
