Jan Marcin Szancer (November 12, 1902–March 21, 1973) was a Polish illustrator.

He studied at the Kraków Academy of Fine Arts, and later in France and Italy.

He was a friend of Jan Brzechwa many of whose poems he illustrated.

Szancer illustrated over 200 books, including Henryk Sienkiewicz's Trilogy, Adam Mickiewicz's Pan Tadeusz and Brzechwa's Pan Kleks series. Beginning in May, 1945, he was the editor and cover-illustrator of the children's magazine Świerszczyk. He was the first (post World War II) artistic director for Telewizja Polska, the Polish broadcasting organization.

The "Crooked House of Sopot" is based on one of his drawings.