This book constitutes the refereed proceedings of the Third International Symposium on AI Verification, SAIV 2026, held in Lisbon, Portugal, during July 24–25, 2026.The 17 full papers and 4 competition contributions were carefully reviewed and selected from 34 submissions. The scope of the symposium was organized into two broad thematic areas. The first area,formal methods for artificial intelligence included topics such as formal specifications, analysis, synthesis, testing, statistical analysis, and explainability for systems with AI components. The second area, artificial intelligence for formal methods focused on AI techniques applied to formal verification, synthesis, safe control, and falsification.