Costanza Sforza of Santa Fiora (1550–1617) was an Italian noblewoman. By birth she was member of the powerful House of Sforza and by marriage member of the House of Boncompagni.

Early life

Costanza was daughter of Sforza Sforza, 10th Count di Santa Fiora (1520–1575) and his first wife, Luigia Pallavicino (died in 1552). She was a granddaughter of Costanza Farnese (daughter of Alessandro Farnese, later Pope Paul III). She married Giacomo Boncompagni, Marquess of Vignola, and Duke of Sora. 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.