Vilainiai Eldership (Lithuanian: Vilainių seniūnija) is a Lithuanian eldership, located in the central-northern part of Kėdainiai District Municipality.

[1] The territory of Vilainiai Eldership is located mostly in the Nevėžis Plain and the Nevėžis river valley.

The relief is mostly flat and cultivated as agriculture lands.

The eastern side is covered by forests.

Following settlements are located in the Vilainiai Eldership (as for the 2011 census):[2]