Costantini is an Italian surname. Notable people with the surname include:
Alessandro Costantini (c. 1581–1583 – 1657), Italian Baroque composer
Bartolomeo Costantini (1889–1941), Italian aviator and racing driver
Celso Benigno Luigi Costantini (1876–1958), Italian cardinal
Eduardo Costantini (born 1946), Argentine businessman
Flavio Costantini (1926–2013), Italian artist
Humberto Costantini (1924–1987), Argentine writer and poet
María Teresa Costantini (born 1949), Argentine actress
Nicholas Costantini (born 1989), Italian footballer
Pierre Costantini (1889–1986), French soldier, journalist, writer and Bonapartist militant
