A driving assisting system for a vehicle comprises a side obstacle detector configured to detect an obstacle present in an obstacle detection area; an obstacle approach prevention controller configured to implement an obstacle approach prevention control which assists an approach prevention for preventing the vehicle from approaching an obstacle detected by the side obstacle detector; an overtaking state detector configured to detect an overtaking state which is at least one of a first state where the vehicle is overtaking the obstacle detected by the side obstacle detector and a second state where the vehicle is estimated to overtake the obstacle. The overtaking state detector is configured to detect the overtaking state based at least on (i) a distance between the vehicle and the obstacle, (ii) a speed of the vehicle relative to the obstacle, and (iii) a detection angle of the obstacle relative to the vehicle.