Roller blind for vehicle roof

The invention relates to a sun blind for a vehicle roof (2) with a roller track (5) that is arranged below the roof and can be wound onto a winding spool (6), whose opposite side edges are guided to be displaceable in the blind movement direction on guide rails (7) and are held in the transverse direction under prestressing of the roller track (5). In order to generate the prestressing in the transverse direction without tensioning elements or spreader bars firmly attached to the roller track (5), which would impede the winding, it is provided that engagement elements guided on the guide rails (7) can be coupled to the side edges of the roller track (5) and that the coupled engagement elements hold the roller track (5) under prestressing in the transverse direction. In this way, the sun blind (4) can be arranged under a curved vehicle roof (2) and follow the roof curvature.