This presentation discusses using a fractional order PID (FOPID) controller tuned by a particle swarm optimization (PSO) technique for automatic voltage regulation (AVR). It begins with an introduction to AVR and conventional PID control. It then describes FOPID controllers and classical tuning methods. Next, it provides details on PSO and how to apply it to optimally tune FOPID controller parameters. Simulation results show the FOPID controller tuned with PSO achieves better dynamic and static performance compared to other tuning methods. In conclusion, a PSO-tuned FOPID controller is developed to improve stability for AVR systems.