A vehicle occupant restraint system is configured to, when a vehicle speed is higher than or equal to a vehicle speed threshold, a steering angle velocity is higher than or equal to a steering angle velocity threshold set for each vehicle speed, and an estimated lateral acceleration is higher than or equal to an acceleration threshold, drive a retractor motor. The steering angle velocity threshold is as a condition to drive the retractor motor. Therefore, by setting an appropriate steering angle velocity threshold according to an amount of movement of an occupant with inertia in a vehicle width direction, the vehicle occupant restraint system is able to take up a webbing when the occupant is estimated to move with inertia by a relatively large amount in the vehicle width direction. The amount of movement with inertia varies for each vehicle speed even at the same steering angle velocity.