Runtuna (local pronunciation Runntúna) is a locality situated in Nyköping Municipality, Södermanland County, Sweden with 250 inhabitants in 2010.

[1] Runtuna has an electoral ward part of the Nyköping East constituency.

The area covers a larger landmass than Runtuna's locality area, being adjacent to the Runtuna parish and the church that is about 4 kilometres (2.5 mi) northwest of the village.

It has also been merged with the electoral district of Ludgo, growing larger during the 1973-2018 period.

This article about a location in Södermanland County, Sweden is a stub.