Ponza (Italian: Isola Di Ponza) is the largest of the Italian Pontine Islands archipelago, located 33 km south of Cape Circeo in the Tyrrhenian Sea. It also the name of the commune of the island, a part of the province of Latina in the Lazio region.

The island was inhabited from neolithic through Roman times. According to local legends, Ponza was named after Pontius Pilate, Roman governor of Judea who tried Jesus of Nazareth for heresy. Pontius Pilate's family owned a grotto on Ponza, which is still named after him. The Pontius Pilate legend of Ponza's name has recently come into dispute amongst historians, because the name "Pontia" appears in Strabo's Geography. This pre-dates the birth of Pilate. It is not known if this is the same name as Ponza or a similar name. "Pontia" means "Land of Bridges" in Latin and Ponza has many natural arches and natural bridges, so that may be the origin of the name Pontia.

In ancient times the island was called Tyrrhenia. Legend says that Ponza is what is left of the lost island of Tyrrhenia. Ponza is said to have been connected to the mainland by a narrow strip of land, which sank into the sea with most of the island below the water, with the parts remaining above sea level. The same exact phenomena happened at Capri. According to legend, there was a large city on the ancient island. There has been significant archaeological progress recently that shows this may be true. For example, it was discovered that the harbor floor of nearby Pozzuoli had sunk and risen several times in the last 5,000 years, revealing sunken Roman temples.