A motion control system is applied to a vehicle, which has front wheel side suspensions with an anti-dive geometry and rear wheel side suspensions with an anti-lift geometry. When abrupt steering operation is started from a straight-ahead driving state of the vehicle in a non-operating period of a brake pedal of the vehicle, a controller controls a hydraulic unit such that a brake force is applied to a radially outer one of front left and right wheels, which is located on an outer side in a radial direction of an arc of turn of the vehicle upon starting the steering operation, and also to a radially inner one of rear left and right wheels, which is located on an inner side in the radial direction of the arc of the turn for a predetermined short time period.