This book constitutes the refereed proceedings of the 5th International Conference on Data and Information in Online, DIONE 2024, held in Sanya, China, during November 1â3, 2024. The 34 full papers were presented in this volume were carefully reviewed and selected from 99 submissions. They focus on Machine Learning and Artificial Intelligence; Optimization and Intelligent Systems; Privacy, Security, and Risk Management; Emerging Applications and Interdisciplinary Research.