The amalgamation of the City of Nybro (instituted in 1932) with its surrounding municipalities took place in 1969.

The municipality was inhabited by a few hundred people until the railways came in the late 19th century, and the town Nybro was in its location between Kalmar on the east coast and Gothenburg on the west coast; later also on the railway from Kalmar and Malmö in the south-west.

Until then Nybro mostly consisted of minor industries, including a match factory, marked by its traditionally Småland forest nature, largely unsuitable for agriculture.

There are nine urban areas (also called localities, Swedish: tätorter) in Nybro Municipality.

This is a demographic table based on Nybro Municipality's electoral districts in the 2022 Swedish general election sourced from SVT's election platform, in turn taken from SCB official statistics.