Vehicle airbag system

A vehicle seat and an airbag system, the seat having a backrest and a squab, extending from the backrest in a longitudinal direction, the backrest extending in height from the squab at a first lower position to a second upper position arranged proximal to shoulders of an occupant in a seated position, the airbag system having an airbag to receive inflating gas from an inflator to inflate the airbag, in which the airbag includes an upper region that extends over a head of the occupant in the seated position and a lower region that extends between a first and second side of the backrest and around a mid-section of the seated occupant, the airbag system having a tether system interconnecting the seat at the second upper position of the backrest and airbag to restrain the lower region of the airbag in the inflated configuration in the longitudinal direction.