Volhynian Voivodeship was a unit of administrative division and local government in the Grand Duchy of Lithuania from 1566 until 1569 and of the Polish Crown within the Polish–Lithuanian Commonwealth from the 1569 Union of Lublin until the Third Partition of Poland in 1795. It was part of the Ruthenian lands in the Lesser Poland Province.

The Union of Lublin was signed on 1 July 1569 in Lublin, Poland, and created a single state, the Polish–Lithuanian Commonwealth, one of the largest countries in Europe at the time. It replaced the personal union of the Crown of the Kingdom of Poland and the Grand Duchy of Lithuania with a real union and an elective monarchy, as Sigismund II Augustus, the last of the Jagiellons, remained childless after three marriages. In addition, the autonomy of Royal Prussia was largely abandoned. The Duchy of Livonia, tied to Lithuania in real union since the Union of Grodno (1566), became a Polish–Lithuanian condominium.