The two-volume set CCIS 1896 and 1897 constitutes the refereed post-conference proceedings of the 5th International Conference on Blockchain and Trustworthy Systems, BlockSys 2023, which took place in Haikou, China during August 8-10, 2023. The 45 revised full papers presented in these proceedings were carefully reviewed and selected from 93 submissions. The papers are organized in the following topical sections:  Part I: Anomaly detection on blockchain; edge intelligence and metaverse services; blockchain system security; empirical study and surveys; federated learning for blockchain.  Part II: AI for blockchain; blockchain applications; blockchain architecture and optimization; protocols and consensus.