Zytturm, Medieval clock tower in Lucerne, Switzerland

Zytturm is a 31-metre tower of the Musegg Wall in Lucerne, standing between the Wachtturm and the Schirmerturm. It is the only tower of the wall with a clock face and a clockwork, and it is the fourth-highest tower of the fortification.

The Zytturm was built in 1442, between the Wachtturm and the Schirmerturm, as one of the nine towers of Lucerne's Musegg Wall. Its clock face and painted decoration were renovated several times over the centuries. Since 1951 the tower has been open to the public from 1 April to 1 November.

The Zytturm holds Lucerne's Erstschlagrecht: its clock strikes one minute before every other clock in the city. Since 2012 the tower houses an exhibition of wrought-iron tower clocks from 1526 to 1914, collected in Lucerne and its surroundings. The idea came from city clockmaker Jörg Spöring (1962–2012) and was realised by the association Turmuhren im Zytturm Luzern, founded in 2011; guided tours are offered.

The tower is open from April through November, allowing visitors to climb to the top for views over the Old Town, lake, and mountains. The best times to visit are early morning or late afternoon to avoid crowds.

The clock mechanism follows an unusual tradition by chiming one minute before the actual hour, a peculiarity rarely found among European tower clocks. This old custom has been maintained across centuries and sets it apart from all modern timekeepers in the city.