A vehicle occupant restraint systems including an airbag which has a first airbag chamber and a second airbag chamber or, more generally, a first partial region and a second partial region. The first and the second airbag chambers are connected to each other so that, as a function of the internal pressures present, gas from the first airbag chamber can flow into the second airbag chamber and gas from the second airbag chamber can flow into the first airbag chamber. The second airbag chamber may include an elastic wall, so that, upon a loading of the first airbag chamber, gas flows into the second airbag chamber and, in the process, elastically expands the second airbag chamber.