Finnish Swedish Heritage Day (Swedish: svenska dagen, Finnish: ruotsalaisuuden päivä) is a general flag flying day, which is celebrated in Finland on 6 November.

Usually, the song Modersmålets sång is sung, celebrating the mother tongue.

The reason why the day of the death of king Gustavus Adolphus was chosen was because this also was the time when the empire of Sweden was founded.

During the language strife of the 1930s the celebrations were overshadowed by street fights between Finnish and Swedish groups.

[4] During the Second World War, both sides stopped fighting each other and emphasized that both language groups were part of Finland, thus the celebration of the day spread outside the political spectrum.