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 Mobile
Agents, 
(v) and Distributed Databases.