A locking element for a quick connector is provided with a matable element releasably connectable to a receiving element of the quick connector. An actuating element is in engagement with the matable element and is mounted within the matable element such that it is displaceable between a released position and a locked position. The actuating element includes a locking device that can be brought into engagement with a retaining ring on an insertable element of the quick connector in an arrangement wherein the locking device is mated with the receiving element in the locked position. Secure attachment of the locking element to the quick connector and ease of use are thereby achieved.