This book constitutes the refereed proceedings of the First International Symposium on Dependable Software Engineering: Theories, Tools, and Applications, SETTA 2015, held in Nanjing, China, in November 2015. The 20 full papers presented together with 3 invited talks were carefully reviewed and selected from 60 submissions.The papers are organized on topical sections on probabilistic systems; hybrid and cyber-physical systems; testing, simulation and inference; bisimulation and correctness; design and implementation; symbolic execution and invariants; and verification and case studies.