Ostaszewski is a Polish masculine surname, its feminine counterpart is Ostaszewska. It may refer to:
Angie Ostaszewski, American TikToker Ostoja-Ostaszewski, Polish noble family Henryk Ostaszewski (1892–1957), Polish lawyer and politician Maja Ostaszewska (born 1972), Polish actress Piotr Ostaszewski (born 1964), Polish historian, political scientist, translator