This book constitutes the refereed proceedings of the 25th International Conference on Runtime Verification, RV 2025, held in Graz, Austria, during September 15–19, 2025. The 22 regular papers, 1 short paper, 2 tool papers, and 1 tutorial paper included in this book were carefully reviewed and selected from 64 submissions. The RV conference focuses on all aspects of formal methods for monitoring, analyzing, and guiding the runtime behavior of software and hardware systems. Runtime verification techniques are essential for ensuring system correctness, reliability, and robustness. They offer an additional layer of rigor and effectiveness beyond conventional testing and are often more practical than exhaustive formal verification.