This book constitutes the refereed proceedings of the 15th International Symposium on Advanced Parallel Processing Technologies, APPT 2023, held in Nanchang, China, during August 4–6, 2023. The 23 full papers and 1 short papers included in this book were carefully reviewed and selected from 49 submissions. They were organized in topical sections as follows: High Performance Computing and Parallelized Computing, Storage Systems and File Management, Networking and Cloud Computing, Computer Architecture and Hardware Acceleration, Machine Learning and Data Analysis, Distinguished Work from Student Competition.