This book constitutes the refereed proceedings of the 36th IFIP WG 6.1 International Conference on Testing Software and Systems, ICTSS 2024, held in London, UK, during October 30–November 1, 2024.The 17 full papers and 5 short papers included in this book were carefully reviewed and selected from 40 submissions. They were organized in topical sections as follows: Best Paper Award; Industry and Challenge Tracks; Mutation Testing and Code Generation; Advancing Code Vulnerability Detec...