A restraint system (10) for helping to protect an occupant (60) of a vehicle (20) having a seat (50) for the occupant (60) includes a primary airbag (70) having a stored condition within a roof (32) and being inflatable to a deployed condition aligned with the seat (50). A support airbag (76) has a stored condition within the roof (32) and is inflatable to a deployed condition engaging the primary airbag (70).