A wind deflector system for a motor vehicle having an end segment for limiting extension of the wind deflector system at the top in the vertical direction, a flexible planar structure fastened to ends of the end segment, and a winding shaft for holding the wound-on planar structure. At least one swivel arm is provided, by means of which the wind deflector system can be transferred from a stowed position to a functioning position with a raised end segment, and a retainer is provided on the planar structure which is arranged, at least when in the functioning position, such that, together with the swivel arm, it restricts mobility of the planar structure relative to the swivel arm in the transverse direction of the vehicle. The system is effective for avoiding the formation of creases in the wound-up planar structure of the wind deflector system.