Plön (Ploen according to the standard conversion of umlauts) is a town in Schleswig-Holstein, Germany. It is the capital of the Kreis (district) of Plön. Population: 13,000.

The town is situated at the shores of two lakes, the Großer Plöner See (Great Lake Ploen) and the Kleiner Plöner See (Lesser Lake Ploen). Hence water is surrounding the town at all sides, leaving just narrow access paths. Plön is the centre of the region called "Holsteinische Schweiz" (Holsatian Switzerland), an area full of lakes and woody hills.

Plön was founded in the 11th century by Slavic peoples. In 1633 a Renaissance castle was built on a hill above the town, being a summer residence for the rulers of Holstein and later for the German emperor Wilhelm II. Today it is a boarding school. The palace grounds are a popular recreation area. They include the Prinzeninsel ("Princes' Island"), which is actually a peninsula and not an island.

At the end of World War II, following the collapse of Berlin, it was temporarily the capital of Germany (Ruhleben barracks).