This volume LNCS constitutes the proceedings of the 31st International Conference on Applications of Natural Language to Information Systems, NLDB 2026, held in Trondheim, Norway, June 17–19, 2026.The 22 full papers presented in this volume were carefully reviewed and selected from 46 submissions. The proceedings contain Generative and Large Language Models; Social Media and Web Data; AI safety and ethics; Efficient/Low-resource methods in NLP; Information Retrieval and Text Mining; Explainable AI; Interpretability and Models Analysis in NLP.