Costantini is an Italian surname. Notable people with the surname include:
Alessandro Costantini (c.1581–1657), Italian Baroque composer Bartolomeo Costantini (1889–1941), Italian aviator and racing driver Celso Benigno Luigi Costantini (1876–1958), Italian cardinal Costantino Costantini, Italian politician and lawyer Dino Costantini Eduardo Costantini (born 1946), Argentine businessman Emilio Costantini Ermenegildo Costantini (1731–1791), Italian painter, active in Rome Fabrizio Costantini Flavio Costantini (1926–2013), Italian artist Francesco Costantini (1827–1899), Italian lawyer and politician Gianluca Costantini (born 1971), Italian cartoonist, artist, Comic journalist, and activist Humberto Costantini (1924–1987), Argentine writer and poet Isela Costantini (born 1971), Argentine politician and businesswoman Livia Nannini Costantini María Teresa Costantini (born 1949), Argentine actress Nicholas Costantini (born 1989), Italian football player Pierre Dominique Costantini (1889–1986), French soldier, journalist, writer and Bonapartist militant Tommaso Costantini (born 1996), Italian football player