This book constitutes the refereed proceedings of the 23rd International Conference on the Integration of Constraint Programming, Artificial Intelligence, and Operations Research, CPAIOR 2026, held in Rabat, Morocco, during May 26–29, 2026.The 37 full papers included in this volume were carefully reviewed and selected from 92 submissions. They focus on new ideas, techniques and applications in Constraint Programming, Artificial Intelligence, and Operations Research.