This volume constitutes the proceedings of 23rd International Conference on Software Engineering and Formal Methods, SEFM 2025, held in Toledo, Spain, on November 10–14, 2025.The 13 full papers and 2 short papers included in this book were carefully reviewed and selected from 39 submissions. The proceedings also include 1 invited short paper. They were organized in topical sections as follows: security and resilience; formal specification and verification; software quality; and artificial intelligence and formal methods.

This volume constitutes the proceedings of 23rd International Conference on Software Engineering and Formal Methods, SEFM 2025, held in Toledo, Spain, on November 10–14, 2025.The 13 full papers and 2 short papers included in this book were carefully reviewed and selected from 39 submissions. The proceedings also include 1 invited short paper. They were organized in topical sections as follows: security and resilience; formal specification and verification; software quality; and artificial intelligence and formal methods.