Lighting assembly for a vehicle headlight having a reflector (1) defining a recess for a lamp; a cover glass (2) having a back face (21) facing the reflector and a front face (22); and a cover glass support part (3) secured to the reflector (1), the support part being provided with fixing device (4, 35) for holding the cover glass (2) securely in place on said support part (3). The fixing device (4, 35) has at least one member (4) forming a pressing contact portion (41) and an actuator portion (42) so as to bring the pressing contact portion into pressed contact against the cover glass (2) by moving the actuator portion, the support part (3) forming an abutment against which the cover glass rests on its front face, the pressing contact portion coming into pressed contact against the back face of the cover glass so as to push the cover glass against the abutment surface or points of the support part. Advantageously, the assembly is provided with two members disposed, for example, in diametrically opposite manner.