Fondi (Latin: Fundi) is a city and comune in the province of Latina, Lazio, central Italy, halfway between Rome and Naples. Before the construction of the highway between the latter cities in the late 1950s, Fondi had been an important settlement on the Roman Via Appia, which was the main connection from Rome to much of southern Italy.
Fondi is the main town of the Plain of Fondi (Piana di Fondi in Italian), a small plain between the Ausoni and Aurunci mountains and the Tyrrhenian Sea. The plain includes three lakes and is agriculturally very fertile. Most in evidence are greenhouses for the production of early crops for sale in Rome. The 15-kilometre (9 mi) long sandy beach stretches from Sperlonga in the south-east to Terracina in the north-west and lies along the Gulf of Gaeta, with views (when the weather is clear) to the Pontine Islands. It is marked by a somehow well-preserved, typical Mediterranean coastal dune landscape.
The territory of Fondi is partially included in the Regional Natural Park of Monti Aurunci.