Kauniainen (Finnish pronunciation: [ˈkɑuniˌɑinen]; Swedish: Grankulla) is a small town and a municipality of 8,772 inhabitants (31 January 2012) in the Helsinki Metropolitan Area, Finland. It is surrounded by the city of Espoo, in Greater Helsinki. Kauniainen was founded by a corporation in 1906, AB Grankulla, that parcelled land and created a suburb for villas; Kauniainen received the status of a market town in 1920, the Finnish name in 1949, and the title of kaupunki ("city, town") in 1972.

The local taxation rate in Kauniainen is the lowest in Finland (16.5%), which makes the city attractive to the highest earners. This in turn makes the average income generally high, making it possible to keep the taxation rate low without compromising the service to the inhabitants.

Approximately 58% of the population have Finnish as their mother tongue while 38% are Swedish speakers. The dominant party in the city council has traditionally been the Swedish People's Party.

Around 10,000 years ago, after the Ice Age, only a few islets were visible in the Yoldia Sea, heights that today form the highest peaks of the area that is today known as Kauniainen. As the land slowly rose Kauniainen became a part of the inner archipelago around 4,000 years ago and there is evidence of human activity in the area in form of pieces of ceramics from this time period. However, the first permanent settlements in the area were established in the 19th century. Today Kauniainen is situated several kilometres from the sea.