Finland Swedish (finlandssvenska) is a general term for standard Finland Swedish and the closely related cluster of dialects of Swedish spoken in Finland by the Swedish-speaking population as their mother tongue. For the most part, these dialects and the dialects spoken in Sweden are mutually intelligible, although some archaic Swedish dialects in Ostrobothnia are practically unintelligible to Swedish-speaking people in southern Finland (and in Sweden). Most Swedish-speaking Finns emphasize that Finland Swedish is not a language separate from the Swedish of Sweden. The Swedish dialects in Finland are considered varieties of Swedish, and the norm for written Standard Swedish is completely applicable also for Finland Swedish.

Swedish as spoken in Finland is regulated by the Swedish Department of the Institute for the Languages of Finland. This regulation includes the officially stated aim of keeping Finland Swedish close to the Swedish as spoken in Sweden and strongly phrased advice against loanwords and calques from Finnish, which are usually incomprehensible to Swedes.

An often repeated "fact" is that the municipality with the highest proportion of Swedish speakers in the world, Hammarland (96%), is located in Finland. Korsnäs has also held this title and is often cited as such. However, as there are no official statistics on the mother tongue of inhabitants of Sweden, this is hard or impossible to verify and should probably be taken with a grain of salt.

In the spoken slang-language, especially among young people in Finnish-dominated areas, Finnish loanwords as well as calques from Finnish are frequently incorporated into Finland Swedish. There are also some words in Finland Swedish that would be considered slightly archaic in Sweden. Some government and public service terms that have been created in recent centuries also differ. The same is true of other new words, notably loanwords from English.

A common mistake made by many Swedes is to mistake Finland Swedish for Swedish with a Finnish accent, something that can be a considerable source of frustration to most native Swedish-speakers in Finland. Any language adopts features, especially pronunciation habits, from dominant languages it comes in touch with, but many of the traits of Finland Swedish exist also in monolingual areas and some are in fact preserved features of old Swedish, as with Scots in comparison to English, Afrikaans in comparison to Dutch, or Galician and Brazilian and African dialects in comparison to modern mainland European Portuguese.

The pronunciation of Finland Swedish by a Swedish-speaking Finn is naturally different from that of Finnish speakers pronouncing Swedish as a foreign language.