Antoni Kazimierz Ostrowski (1713–1784) was a Polish priest and politician. He was bishop of Inflanty (1753–1763), bishop of Kujawy (1763–1776) and archbishop of Gniezno (also, Primate of Poland) (1777–1784). He was one of the Polish nobles in Russian service and supported their position, including presiding over the Partition Sejm in 1773–1775.