A driving assistance system includes: a target sensor; an operation amount sensor; a speed sensor; and an electronic control unit configured to perform pre-collision control when a predetermined control start condition is satisfied, and not to perform, even when the predetermined control start condition is satisfied, the pre-collision control when a permission condition has not been established by a point in time at which the predetermined control start condition is satisfied, the permission condition being that the accelerating operation amount is equal to or larger than a first operation amount threshold value and the vehicle speed is equal to or less than a speed threshold value.