Frederiksberg (Danish pronunciation: [fʁeðʁeksˈpɛɐ̯ˀ, fʁæðʁæksˈpɛɐ̯ˀ]) is a part of the Capital Region of Denmark. It is an independent municipality, Frederiksberg Municipality, separate from Copenhagen Municipality, but both are a part of the region of Copenhagen. It occupies an area of less than 9 km² and had a population of 103,192 in 2015. It is the most densely populated municipality in Denmark.

Frederiksberg is an enclave surrounded by Copenhagen Municipality. Some sources ambiguously refer to Frederiksberg as a quarter or neighbourhood of Copenhagen, being one of the four municipalities in Copenhagen zone (the other three being Copenhagen, Tårnby and Dragør). However, Frederiksberg has its own mayor and municipal council, and is fiercely independent.

Frederiksberg is an affluent area, characterised by its many green spaces such as the Frederiksberg Gardens, Søndermarken, and Hostrups Have. Some institutions and locations that are widely considered to be part of Copenhagen are actually located in Frederiksberg. For example, Copenhagen Zoo as well as several stations of the Copenhagen Metro (the stations Forum, Frederiksberg, Fasanvej, Lindevang, Flintholm, Axel Møllers Have, and Frederiksberg Allé) are located in Frederiksberg. The Copenhagen S-train system also has several stations in Frederiksberg, including Peter Bangs Vej station and Flintholm station.

Frederiksberg's original name was Tulehøj, a combination of the Danish words thul (thyle) and høj (high), indicating that a thyle lived there, the reciter of eldritch times.^{[further explanation needed]} The term is known from the Snoldelev rune stone. In Beowulf, Unferth holds the same title. In Håvamål, Odin himself is referred to as "the old thul". Thula translates as "song", like in the Rigsthula poem from the Edda. By 1443 the name Tulehøj was spelled Tulleshøy. It was regarded as Copenhagen's border to the west. People have lived in the area since the Bronze Age.

The history of Frederiksberg goes back to 2 June 1651 when King Frederik III gave 20 Danish-Dutch peasants the rights to settle at Allégade (from the words allé (tree-lined street or avenue) and gade (street)), and founded the town then named "Ny Amager" (New Amager) or "Ny Hollænderby" (New Dutchman-town) as part of a general policy of introducing modern, Dutch farming techniques into Denmark, a policy begun by King Christian IV. Farming was not very successful, and additionally, in 1697 most of the town burned down. This meant that the peasants were unable to pay taxes, and the land reverted to the crown, by now Frederik III's son Christian V.

In 1700–1703, King Frederik IV built a palace on top of the hill known as Valby Bakke (bakke = hill). He named the palace Frederichs Berg, and the rebuilt town at the foot of the hill consequently changed its name to Frederiksberg. A number of the local houses were bought by wealthy citizens of Copenhagen who did not farm the land, but rather used the properties as country houses.

The town changed slowly from a farming community to a merchant town, with craftsmen and merchants. During the summer, rooms were offered for rent, and restaurants served food to the people of Copenhagen who had left the cramped city for the open land, and to be near the royals.

Initially the town grew slowly with population growing from 1,000 in 1770, to 1,200 in 1800, and to 3,000 in 1850.