The Principality of Drutsk (Belarusian: Княства Друцкае; obsolete spelling: Druck) was a small appanage of the Principality of Polotsk, centred in the city of Drutsk.

[1] It was located on a three way stick between Vitebsk, Minsk and Mogilev regions in modern Belarus.

Soon its territory was taken over by another appanage duchy of Polotsk, Principality of Minsk governed by Gleb Vseslavich.

It is believed that Algirdas, Grand Duke of Lithuania, acquired the Principality by marriage to Maria of Vitebsk.

The principality became part of the Grand Duchy of Lithuania where it existed as an autonomous principality until an administrative reform in 1565–1566, when it was included into the Orsha county of Vitebsk Voivodeship.