A time-setitng mechanism comprises all the components intended to adjust the time indicated by the watch. The number of its components may vary depending on the constructions, and many of them also belong to the winding mechanism. The components of the time-setting mechanism are:

Only intermediate wheel(s) is/are specific to the time-setting mechanism.

Until the mid-19th century, time-setting mechanisms were relatively rudimentary and required the use of a key (similar to a clock time-setting mechanism). Through a hole, drilled at the case back, one could directly connect the key to a square located at the end of the centre pinion, protruding on the surface of its bridge. This system has the advantage of being mechanically simple and easy to manufacture. However, it still requires the use of an external accessory (the key), and any water-resistance of a case with such a time-setting system is illusory.

The invention in 1847 of a combined winding and setting mechanism by Antoine Le Coultre sounded the death knell for winding and time-setting mechanisms that were using keys. All corrections (winding and time-setting) since were done through the crown. This invention also contributed, a few years later, to the production of the first waterproof watches.