Sieradz Voivodeship (Polish: Województwo sieradzkie, Latin: Palatinatus Siradiensis) was a unit of administrative division and local government in the Kingdom of Poland and the Polish–Lithuanian Commonwealth, from 1339 to the second partition of Poland in 1793.

The seat of the voivode was in Sieradz, while local sejmiks took place in Szadek.

The history of Sieradz Voivodeship dates back to the year 1138, when following the Testament of Bolesław III Krzywousty, Poland was divided into several smaller duchies.

In 1290–1300, and after 1306, Sieradz was ruled by Duke Wladyslaw Lokietek, who incorporated it back into the Kingdom of Poland.

When in 1396 the Wieluń Land returned to Poland, it became part of Sieradz Voivodeship, which increased the area to 212.25 old-Polish sq.