This book constitutes the refereed proceedings of the 5th International Conference on Dependability in Sensor, Cloud, and Big Data Systems and Applications, DependSys, held in Guangzhou, China, in November 2019. The volume presents 39 full papers, which were carefully reviewed and selected from 112 submissions. The papers are organized in topical sections on dependability and security fundamentals and technologies; dependable and secure systems; dependable and secure applications; dependability and security measures and assessments; explainable artificial inteligence for cyberspace.