This two-volume set LNCS 16367 -16368 constitutes the proceedings of the 26th International Conference on Web Information Systems Engineering, WISE 2025, held in Marrakech, Morocco, in December 15–17, 2025.The 54 full papers and 22 short papers were presented in these proceedings were carefully reviewed and selected from 140 submissions. The papers have been organized in the following topical sections as follows: AI and Machine Learning; Recommender Systems I; Web Applications and Services; Security and Privacy; Large Language Models I; Deep Learning and Networks; Knowledge Graphs I; Security and Networking; Security and Trust; Sentiment Analysis and Classification.