Piazza della Cisterna is a piazza in San Gimignano, Italy. It has a triangular shape with a slight natural slope and is connected to the nearby Piazza del Duomo by an open passage. The pavement is brick and the piazza is surrounded by houses and medieval towers. There are presently 5 towers onto the square or very near it and the bases of other five are visible on the facade of the various palaces, plus one, the Ridolfi tower, which is no longer in existence having collapsed in 1646 onto the family palace, which divided the square in two alongside the short axis, thus making this relatively small area a concentrate of medieval architecture. In the south-west corner, the piazza meets the Arc of Becci, (l'arco dei Becci), an ancient city gate. The arc is flanked by the massive rectangular towers of Becci (torri dei Becci) on the left and Cugnanesi (torri dei Cugnanesi) on the right.

Past the access to via di Castello on the east side, which led down to the original Bishop’s castle, the northern side of the square is occupied by the renaissance Cortesi Palace, which extended up to the torre del Diavolo, and extends along the north side of the square including the old houses of the Cattani family. The remains of two pre-existing towers of the Cattani palace are clearly visible onto the facade of the Cortesi Palace.

The west side is adorned with various towers, like the twin towers of Ardinghelli and the tower of palazzo Pellari visible over the roofs.

The piazza is located at the intersection of two main streets of the village of San Gimignano: la via Francigena that run north to south and la via Pisa - Siena that runs east to west. The piazza was used as a market and a stage for festivals and tournaments. Originally the area was divided in two squares by the palace and tall tower of the Ridolfi family, the Piazza dell’ Olmo in the inferior and western part and the Piazza delle Taverne in the eastern side and with the cisterna in the middle. In 1646 the tall Ridolfi tower suddenly collapsed, destroying the palace and thus the two squares were merged into one, the Piazza della Cisterna.

The piazza is named after the underground cistern (Cisterna) built in 1287. The cistern is capped by a travertine octagonal pedestal, which was built in 1346 under the mayor Guccio Malavolti whose coat of arms with the ladder is carved onto the stones, and is close to the center of the square.

• Toscana. Guida d'Italia ("Guida rossa"), Touring Club Italiano, Milano, 2003.

43°28′2.79″N 11°2′36.89″E / 43.4674417°N 11.0435806°E / 43.4674417; 11.0435806