Pori (Finnish: [ˈpori]; Swedish: Björneborg [bjœːrneˈborj] ^ⓘ; Latin: Arctopolis) is a city in Finland and the regional capital of Satakunta. It is located on the west coast of the country, on the Gulf of Bothnia. The population of Pori is approximately 83,000, while the sub-region has a population of approximately 128,000. It is the 10th most populous municipality in Finland, and the eighth most populous urban area in the country.

Pori is located some 10 kilometres (6 mi) from the Gulf of Bothnia, on the estuary of the Kokemäki River, 110 kilometres (68 mi) west of Tampere, 140 kilometres (87 mi) north of Turku and 241 kilometres (150 mi) north-west of Helsinki, the capital of Finland. Pori covers an area of 2,062.00 square kilometres (796.14 sq mi) of which 870.01 km² (335.91 sq mi) is water. The population density is 71.8/km² (186/sq mi).

Pori was established in 1558 by Duke John, who later became King John III of Sweden. The municipality is unilingually Finnish. Pori was also once one of the main cities with Turku in the former Turku and Pori Province (1634–1997). The neighboring municipalities are Eurajoki, Kankaanpää, Kokemäki, Merikarvia, Nakkila, Pomarkku, Sastamala, Siikainen and Ulvila.

Pori is especially known nationwide for its Jazz Festival, Yyteri's sandy beaches, Kirjurinluoto, Porin Ässät ice hockey club, FC Jazz football club, which won two championships in the Veikkausliiga in the 1990s, and Pori Theater, which is the first Finnish-language theater in Finnish history. Pori is also known for its local street food called porilainen. During its history, the city of Pori has burned down nine times; only Oulu has burned more often, as many as ten times. The current coat of arms of Pori was confirmed for use by President P. E. Svinhufvud on December 11, 1931, and was later redrawn by Olof Eriksson. The city council reaffirmed the use of the redrawn version on October 27, 1959. The bear motif of the coat of arms comes from a 17th century seal and the motto, deus protector noster or "God is our protector", is also on the coat of arms of the city's founder, Duke John.

The Finnish name Pori comes from the -borg part (meaning citadel, fortress or castle) of the original name in Swedish with a Fennicised pronunciation. The whole Swedish name Björneborg literally means Bear Fortress or Bear Castle (Finnish: Karhulinna), and the Latin-Greek Arctopolis means Bear City (Finnish: Karhukaupunki).

City of Pori was established on March 8, 1558 by Duke John of Finland (Finnish: Juhana III or Juhana-herttua) who was later known as John III of Sweden. It was a successor to the medieval towns of Teljä (Kokemäki) and Ulvila. Sailing the Kokemäki river had become more and more difficult since the 14th century due to the post-glacial rebound. The importance of Kokemäki and Ulvila began to decline as the ships could no longer navigate the river. In the 16th century the situation had become so bad that Duke John decided to establish a new harbour and market town closer to the sea.

The Bourgeoisie of Ulvila were ordered to migrate to the newly founded city and on 8 March 1558 John III gave the charter of Pori, which read: "Because we have seen that it would be best to build a strong market town alongside the sea, and because we cannot find anywhere suitable for fortifying in Ulvila, we have chosen another location at Pori."

At the beginning Pori had around 300 involuntary residents. However, they soon recognized the advantages of their new location, which offered opportunities for profitable trading, among other things. Ship building has been important since the beginning of history of Pori. Shipyard started by the river in 1572 and it worked until the early 20th century. The biggest ship probably ever built in Pori was "Porin Kraveli," completed in 1583.