Nykarleby is a bilingual municipality with Finnish and Swedish as its official languages.

[6] A Swedish-speaking art school (Svenska Konstskolan) is located in Nykarleby town.

In 1620, the small village of Lepua was chartered as a city, with the Swedish name Nykarleby, which means 'New Karleby'; the Finnish name is a Finnicized version of the same.

The town was chartered in the same year as the nearby city of Kokkola, or in Swedish, Gamlakarleby (later, Karleby).

The battles of Nykarleby and Jutas were fought there between Swedish and Russian troops during the Finnish War in 1808.