A braking force control system for a motor vehicle, in which a hydraulic pressure control device controls a hydraulic pressure generated by the master cylinder or the pump, in such a way that a target braking torque (Nr in FIG. 1) is calculated from a target slip factor (Sr) and an actual slip factor (S), the target braking torque (Nr) is converted into a target braking hydraulic pressure (Pr), and that an estimative braking hydraulic pressure (P) currently under action is calculated by the use of a hydraulic pressure model, while the controlled variable of the hydraulic pressure control device is calculated from the estimative braking hydraulic pressure (P) and the target braking hydraulic pressure (Pr) by the use of a reverse hydraulic pressure model. Thus, the hydraulic pressure can be controlled in conformity with the actual motion state of the motor vehicle.