Ostrobothnian Swedish is a variety of Finland-Swedish, spoken in Finland. Outside the autonomous island province of Åland, which is officially monolingually Swedish, Ostrobothnia is the only region of Finland where the Swedish-speakers have a majority (the majority being 51%). Ostrobothnian Swedish-speakers are traditionally farmers, and as such, isolation of the communities produces strong dialectal variations.

One famous Swedish dialect in Ostrobothnia is the Närpes dialect, whose mutual intelligibility with other forms of Swedish is questionable. Finland-Swedes have difficulties with understanding the Närpes dialect, and it is almost unintelligible to anyone else, so speakers of the Närpes dialect have to learn their standard Swedish well.

The most archaic Nordic dialects in Scandinavia are found in Ostrobothnia, Icelandic excluded. The abovementioned Närpes dialect is in syntax, grammar and vocabulary fairly close to Icelandic, hence the difficulties in understanding.