This volume constitutes the proceedings of the 19th IFIP WG 11.12 International Symposium on Human Aspects of Information Security and Assurance, HAISA 2025, held in Mytilene, Greece, during July 7–9, 2025. The 30 full papers presented were carefully reviewed and selected from 38 submissions. The papers are organized in the following topical sections: Awareness & Education; Security Culture; Privacy and Technical Attacks & Defenses.