This two part LNCS 15227 and 15528 volumes constitutes the proceedings of the 20th IFIP WG 10.3 International Conference on Network and Parallel Computing, NPC 2024, which was held in Haikou, China, during December 7-8, 2024. The 76 full papers presented in this volume were carefully reviewed and selected from 200 submissions. They are organized according to the following topics: Part-I : High-performance and Parallel Computing; Novel Memory and Storage Systems; and Emerging Architectures and Systems. Part-II : Edge Computing and Intelligence; Federated Learning Algorithms and Systems; Emerging Networks; and In-network Computing and Processing.