In a vehicle occupant protection system comprising a seat for seating a vehicle occupant in a passenger compartment of a vehicle, and a seat belt for restraining a vehicle occupant seated in the seat, the seat belt is pulled rearward by a power actuator in an early stage of a vehicle crash to apply deceleration to the vehicle occupant before the vehicle body has started decelerating so that the vehicle occupant is prevented from being subjected to a deceleration level which is higher than an unacceptable level of deceleration throughout the entire period of the vehicle crash.