Count Jan Sebastian Szembek (1672-1731[1]) was a Polish szlachcic.

He was Recorder of the Crown starting in 1699,[2] Vice-Chancellor of the Crown in 1702,[3][4] and Grand Chancellor of the Crown since 1712.

[5] He was also the starost of Łomża in 1706.

Marshal of the Sejm (zwyczajnego) on December 22, 1701 - February 6, 1702.

This biography of a Polish noble is a stub.