An airbag module for protecting an occupant of a vehicle seat. The module includes an inflatable cushion and an inflator for providing inflation gas for the cushion. The cushion includes at least a first inflatable chamber and a second inflatable chamber. The inflatable cushion is configured so that the first inflatable chamber fully inflates prior to the second inflatable chamber becoming fully inflated. The second inflatable chamber is positioned to absorb energy resulting from movement of the head of the occupant, and the loft of the second inflatable chamber is greater than the loft of the first inflatable chamber.