An illumination system for an interior of a motor vehicle includes a sensor, with which an environmental lighting situation is able to be detected, as well as an illumination device for illuminating the motor vehicle interior. The illumination system has a controller that is subordinate to the sensor and is superordinate the illumination device. The controller adjusts an interior lighting situation depending on the environmental lighting situation that is influenced by actual objects located in the environment of the motor vehicle, by lights of the illumination device.