A disc brake for a utility vehicle has a brake caliper engaging over a brake disc, at least one application device for applying the disc brake by way of a displaceably guided bridge, which bridge has at least one threaded hole, into which an actuating spindle passing through a closure plate connected to the brake caliper and provided with an external thread is screwed. The spindle bears a pressure piece which can be rotated relative thereto, by which pressure piece a brake pad can be pressed against the brake disc. A readjusting device is operatively connected to the actuating spindle for readjusting a clearance. A securing ring is provided, which is held on the bridge so as to be secured axially and against rotation and which, in an end position of the actuating spindle screwed in counter to the actuating direction, in order to secure the actuating spindle against rotation, engages with a form fit in a thread-free end region of the actuating spindle which is assigned to the pressure piece.