This book gathers the proceedings of the 12th International Conference on Advanced Concepts in Mechanical Engineering (ACME), held in Iași, Romania, on June 4–5, 2026. It presents advances and innovations in mechanical engineering and includes topics such as Machine Design, Tribology; Materials and Surface Engineering; Mechatronics, CAD, Mechanical Vibrations; Theory of Mechanisms and Machinery, Robotics; Mechanics of Deformable Bodies; Automotives, Engine and Transmission, Road Safety; Applied Thermodynamics, Heat Transfer, and Renewable Energy, Thermal Systems; Technologies in Agriculture and Food Processing.