Side airbag and method of folding

A method and apparatus for providing a side airbag device for use in a vehicle, comprising: an inflatable cushion (10) for deployment from an unexpanded state to an expanded state. The inflatable cushion (10) is positioned behind a headliner (40) of the vehicle in an un-inflated state, and the inflatable cushion (10) is configured to traverse a side of the vehicle when it is inflated. The inflatable cushion (10) also comprising a deploying edge (32;50) that defines a portion of a periphery of the inflated cushion (10), wherein the inflatable cushion is folded in a manner that causes the deploying edge (32;50) to deploy as a first leading edge as said inflatable cushion (10) is inflated to an expanded state by an inflator wherein the deploying edge (32;50) is the first portion of the inflatable cushion (10) to expand around the headliner.