An electric power steering system includes a motor control device that controls driving of a motor based on an assist command value, the motor applying assist torque to a steering mechanism. The motor control device computes a first assist component based on steering torque and a vehicle speed. The motor control device computes a second assist component based on the steering torque and the first assist component. The motor control device computes the assist command value by adding the second assist component to the first assist component. The motor control device includes a road information compensation portion that adjusts the second assist component contained in the assist command value. A basic assist component computation portion computes the first assist component in accordance with a degree of adjustment of the second assist component.
