Velletri is an Italian comune in the Metropolitan City of Rome, approximately 40km to the south-east of the city centre, located in the Alban Hills, in the region of Lazio, central Italy. Neighbouring communes are Rocca di Papa, Lariano, Cisterna di Latina, Artena, Aprilia, Nemi, Genzano di Roma, and Lanuvio. Its motto is: Est mihi libertas papalis et imperialis.
Velletri was an ancient city of the Volsci tribe. Legendarily it came into conflict with the Romans during the reign of Ancus Marcius, the fourth king of Rome; then again in the fifth and fourth centuries BCE, during the early Roman Republic. Velletri was also the home of the Octavii, the paternal family of the first Roman Emperor Augustus. In the Middle Ages, it was one of the few "free cities" in Lazio and central Italy. It was the site of two historic battles in 1744 and 1849. During the Second World War, it was at the centre of fierce fighting between the Germans and the allies in 1944 after the Anglo-American landing at Anzio.
Today, Velletri is home to a circuit court and a prison, in addition to several colleges and high schools.