This book constitutes the refereed proceedings of the Third EAI International Conference on Security and Privacy in Cyber-Physical Systems and Smart Vehicles, SmartSP 2025, held in Salt lake City, UT, USA, during December 1–2, 2025.

The 10 full papers, 6 short papers, 2 special tracks, and 2 demo papers included in this book were carefully reviewed and selected from 48 submissions. They are organized into the following topical sections: Secure CPS and IoT; Attacks against CPS and IoT; Threat Detection and ML Security; and Special Topic: Human-Machine Interfaces in Smart Vehicles.