The two-volume set IFIP AICT 721 +722 constitutes the proceedings of the 18th IFIP WG 11.12 International Symposium on Human Aspects of Information Security and Assurance, HAISA 2024, held in Skövde, Sweden, in July 9-11, 2024. The 39 full papers presented were carefully reviewed and selected from 55 submissions. The papers are organized in the following topical sections: Part I - Management and Risk; Social Engineering; Technical Attacks and Defenses; Usable Security. Part II - Awareness and Education; Privacy.