Driving assistance system

A driving assistance system includes an electronic control unit and a notifying unit. The electronic control unit detects an inter-vehicle distance and relative velocity, controls the subject vehicle, performs a first notification operation when the inter-vehicle distance becomes equal to or larger than a first distance and the relative velocity becomes equal to or higher than a first velocity, or equal to or larger than a second distance, sets an inter-vehicle distance when the forward vehicle and the subject vehicle are stopped as a reference inter-vehicle distance and performs a second notification operation when a difference between the reference inter-vehicle distance and the inter-vehicle distance becomes equal to or larger than a third distance. The electronic control unit does not perform the second notification operation at least until after the first notification operation is performed.