Velletri is an Italian comune situated in the region of Lazio in central Italy. It is located within the Metropolitan City of Rome, approximately 40 km to the southeast of Rome's city centre. The municipality is positioned in the Alban Hills and is bordered by several neighboring communes, including Rocca di Papa, Lariano, Cisterna di Latina, Artena, Aprilia, Nemi, Genzano di Roma, and Lanuvio.
The town's official motto is "Est mihi libertas papalis et imperialis."