This book constitutes the proceedings of the 33rd Irish Conference on Artificial Intelligence and Cognitive Science, AICS 2025, held in Dublin, Ireland, during December 1&2, 2025. The 33 full papers presented in these proceedings were carefully reviewed and selected from 122 submissions. These papers cover themes such as applications of AI, machine learning and deep learning methods, dataset construction and analysis, AI for social good, AI ethics and responsible AI, cognitive science and learning theory, and semantic web technologies. They reflect both theoretical advances and practical applications of AI technologies in different domains.