This book constitutes the proceedings of 25th International Symposium, SSS 2023, in Jersey City, NJ, USA, in October 2023.The 32 full papers presented together with 8 short papers were carefully reviewed and selected from 78 submissions. The conference was organized into five tracks reflecting major trends related to the conference: (i) Track A. Self-stabilizing Systems:Theory and Practice, (ii) Track B. Distributed and Concurrent Computing:Foundations, Fault-Tolerance and Scalability, (iii) Track C. Cryptogrophy and Security, (iv) Track D. Dynamic, Mobile and Nature-Inspired Computing MobileAgents, (v) and Distributed Databases.