The invention relates to a curtain protector with cooling for thermal or photovoltaic solar panels, for mounting on at least one of said panels, forming a unit. The invention consists of a curtain or blind (5) which opens or closes on a motorized (11) axle (12). The curtain is mounted on a frame (2) comprising rails (9) along which it runs. Gears or rollers (8, 16, 17) can be arranged on the ends of the rails in order to facilitate the movement. At least one extractor (3) facilitating the cooling of the panel by ventilation is arranged between the box (4) and the panel (1). The curtain is closed by the drive of the motorized (11) axle (12) together with a traction mechanism on the other end of the curtain by means of springs, struts (10) and cords (7) or the like. The protector assembly comprises activity and weather condition sensors that activate the motor in order to move the curtain, protecting the panels in the event of over-heating or inactivity.