A vehicle occupant protection system for a convertible includes an airbag disposed in the door. The airbag has a lower cell area, an upper cell area, and an intermediate area. The intermediate area, in a filled state of the airbag has a smaller thickness than the lower cell area and/or the upper cell area. A positioning strap has one end fastened to the vehicle at a fastening location, and a second end fastened to a fastening point at the intermediate area. A length of the positioning strap between the fastening location and the fastening point is configured to be shorter than a length of an airbag fabric between a lower edge of the airbag and the intermediate area of the airbag.