Santo Stefano dei Cavalieri, Church in Knights Square, Pisa, Italy.

Santo Stefano dei Cavalieri is a church on Piazza dei Cavalieri in Pisa, built from 1565 for the Order of Knights of Saint Stephen. Its white Carrara marble facade, by Don Giovanni de' Medici with Alessandro Pieroni, has two orders of columns and a tympanum bearing the Medici and Order arms. The single nave was given side aisles in 1859 by Gaetano Niccoli; the bell tower by Vasari was finished in 1572 by Giovanni Fancelli.

Construction began in 1565 under Grand Duke Cosimo de Medici to serve the Order of Knights of Saint Stephen. It replaced an earlier church from 1074 that had occupied the same location.

The church's name comes from its role as the chapel of the Order of Knights of Saint Stephen, founded by Cosimo I de' Medici. The holy water fonts were carved by Giovanni Fancelli in 1568 from a design by Vasari. The five monochrome paintings on the counter-facade are the only surviving decoration from the 1588 entry of Grand Duke Ferdinando II.

The church stands on Piazza dei Cavalieri, in the historic centre of Pisa, and is still used for worship only, granted by the state property office to the diocese, whose bishop appoints the rector. Access is through the square, and the interior is entered from the facade side. Part of the roof was rebuilt in 2014 after water infiltration, so some areas may be closed for maintenance.

The 1604 ceiling by carver Bartolomeo Atticciati holds six painted panels, each tied to a specific event: Il Cigoli shows Cosimo I receiving the knightly habit, Ligozzi the fleet's return from Lepanto and the sack of Preveza, Allori Maria de' Medici embarking at Livorno, L'Empoli the victory in the Greek archipelago and the capture of Bône.