Prince Kazimierz Nestor Sapieha (1757–1798) was a Polish-Lithuanian noble (szlachcic) and one of the creators of the 3 May Constitution.

Kazimierz Sapieha was educated at the Knight School in Warsaw from 1767 until 1771, and later studied in Italy.

[1] An early supporter of the magnate opposition to any liberalization (his uncle Hetman Franciszek Ksawery Branicki was its leader), Sapieha changed his position under the influence of Stanisław Małachowski, and became a supporter of reforms, and the 3 May Constitution.

[1] He strongly protested, when King Stanisław August Poniatowski joined the Targowica Confederation, and this so angered Sapieha, that he decided to leave Poland.

[1] After the Uprising collapsed, he left Poland again and spent the rest of his life in exile in Vienna, where he died in 1798.