A game system includes a game apparatus and left and right controllers. The game apparatus includes a swing determination unit that receives operation data from the left/right controllers and determines whether a swing input is being performed onto the left/right controllers on the basis of the received operation data, and includes a vibration data generator configured to generate vibration data such that, when the swing input is being performed onto the left controller, a vibration actuator of the left controller is caused to vibrate with a predetermined intensity and a vibration actuator of the right controller is caused to vibrate with a lower intensity, and when the swing input is being performed onto the right controller, the vibration actuator of the right controller is caused to vibrate with a predetermined intensity and the vibration actuator of the left controller is caused to vibrate with a lower intensity.