Costanza Sforza of Santa Fiora (1550 – 22 January 1617) was an Italian noblewoman.

Costanza was daughter of Sforza Sforza, 1st Marquess of Castell'Arquato, 11th Count of Santa Fiora (1520 – Castell'Arquato, 21 October 1575), and his first wife Luigia Pallavicino (died in 1552), maternal granddaughter of Jacopo Salviati and wife Lucrezia de' Medici.

[1] She married Don Giacomo Boncompagni, 1st Marquess of Vignola, and 1st Duke of Sora, Aquino, Arce and Arpino, on 5 February 1576, and had fourteen children.

[2] Lavinia Fontana, a prominent Bolognese artist, painted her portrait in 1594.

A year later, Constanza served as the namesake and godmother of Fontana's daughter.