Opposition parties (20) Independent (3) The Masovian Voivodeship Sejmik (Polish: Sejmik Województwa Mazowieckiego) is the regional legislature of the Voivodeship of Masovia in Poland.

It is a unicameral parliamentary body consisting of fifty-one councillors, making it the largest provincial assembly in the republic.

Incumbent chairperson of the assembly is Ludwik Rakowski of the Civic Coalition, elected at the first session on 7 May 2024.

The current executive board of Masovia is a coalition government between the Civic Coalition and Polish People's Party under the leadership of Marshal Adam Struzik of the PSL.

Members of the assembly are elected in seven multi-member constituencies with the party-list proportional representation using D'Hondt apportionment method.