Kauniainen (Finnish: [ˈkɑu̯niˌɑi̯nen]; Swedish: Grankulla) is a town in Finland, located in the southern interior of the country. Kauniainen is situated in the southern part of the Uusimaa region, and it is enclaved by the City of Espoo. The population of Kauniainen is approximately 10,000. It is the 95th most populous municipality in Finland. Kauniainen is part of the Helsinki Metropolitan Area, which has approximately 1.62 million inhabitants.

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 municipal taxation rate in Kauniainen is the lowest in Finland (%), which has made the city attractive to high-income families. 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.

Kauniainen is a bilingual municipality with Finnish and Swedish as its official languages. The population consists of 59% Finnish speakers, 30% Swedish speakers, and 11% speakers of other languages. The dominant party in the city council has traditionally been the Swedish People's Party.

The Swedish name Grankulla is composed by the Swedish words "gran" (spruce) and "kulle" (hill) and has been in use in this form since the beginning of the 1900s. Earlier the place was known under its dialectal form Gränkull. The name Gränkull is found on modern maps as the name of the hill where the water tower in Kauniainen is located. The Finnish name of the town, Kauniainen, is derived from the name of a homestead that was located in Kauniainen called Kauniais. It was named after an estate near Tampere. The Finnish name was taken into use in the 1930s and was made the official name of the town alongside the Swedish name in 1949.

The explanation for the coat of arms is "a golden, red squirrel sitting on a blue plate, holding a black spruce cone in its forefeet, with three golden roses side by side above it." The squirrel holding the spruce cone of the coat of arms indirectly refers to the Swedish name of Kauniainen (Grankulla). The roses on the subject depict the villa settlements in the locality. The coat of arms was designed by Ahto Numminen and approved by the Kauniainen Chamber of Commerce at its meetings on June 5, 1951, and January 10, 1952. The Ministry of the Interior confirmed the use of the coat of arms on March 11 of the same year.

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.

In the beginning of the 20th century Kauniainen only consisted of a few crofters' holdings at the outskirts of larger farms in Espoo. The name of the place, Grankulla, was known as the more dialectal Gränkull. The main road between Helsinki and Turku had passed through the northern parts of Kauniainen for centuries, but the new railway between the same cities that opened in 1903 was crucial for the development of the area.