This book constitutes the refereed proceedings of the 19th International Conference on Informatics in Schools: Situation, Evolution, and Perspectives, ISSEP 2026, held in Tallinn, Estonia during September 20–23, 2026. The 13 full papers, 1 short paper and 1 keynote paper presented were carefully reviewed and selected from 34 submissions. The papers cover the following topics: Curriculum, Policy, and the Future of Informatics Education; Teaching and Learning Informatics; Computational Thinking and Learner Diversity.