This book constitutes the refereed proceedings of the 18th Asian Conference on Recent Challenges in Intelligent information and Database Systems, ACIIDS 2026, held in Kaohsiung, Taiwan during April 13–15, 2026. The 81 full papers included in this book were carefully reviewed and selected from 431 submissions. They were organized in topical sections as follows: Deep Learning Methods and Architectures; Generative, Foundation and Large Language Models; Explainable, Trustworthy and Responsible AI; Graph-Based Learning and Knowledge Systems; Image, Video and Multimedia Processing; Speech and Natural Language Processing; Optimization and Intelligent Decision Systems; Intelligent Systems for Healthcare and Bioinformatics; Federated, Distributed and Edge Intelligent Systems; Intelligent Applications in Industry, Management and Smart Infrastructure; Security, Privacy and Adversarial Learning.