This book constitutes the refereed post proceedings of the 15th International Conference on Subject-Oriented Business Process Management, S-BPM ONE 2024, held in Weiden, Germany, during May 21-22, 2024. The 14 full papers and 8 short papers included in this book were carefully reviewed and selected from 30 submissions. These papers have been organized in the following topical sections: Processes And Data; Subject-Oriented Modeling, Philosophy, and Technology; Processes and Sustainability; Good Process Practices.