The House of Działyński was a Polish noble family whose name comes from their original place of settlement, Działyń in Dobrzyń Land. They used the Ogończyk coat of arms.
The original head of the family was Piotr from Działyń (died 1441). During the 16th century the members of the Działyński family began moving from Kujawy into Royal Prussia. Their connections with the court of the King of Poland allowed them to quickly acquire senatorial positions in the Prussian Diet on the Prussian side of the family (the family had sixteen Prussian senators between the 15th and 18th centuries). In the second half of the 17th century some members began moving to Wielkopolska and over time this became the dominant line of the family. The last male member of the family, Jan Kanty Działyński died in 1880.