The invention relates to an inflatable side impact protection system for an occupant of a vehicle having a side-panel and a window section in the side-panel. The protection system comprises a gas bag which when packed has a specific pack length, a gas generator for inflating the gas bag, and a side-panel covering. The window section is provided which has a lower edge, the side-panel covering having an upper end piece which terminates the covering at the lower edge of the window section. The gas bag when packed is arranged under the end piece and in a deployed state covers the vehicle side panel over a large area for protecting at least one of the thorax and pelvic region of the occupant. The end piece is constructed, at least over sections, as a flap which, when swung open, defines a downward pointing ejection channel for the gas bag.