Arcinazzo Romano is a comune (municipality) in the Metropolitan City of Rome in the Italian region of Lazio, located about 50 kilometres (31 mi) east of Rome.

Arcinazzo Romano borders the following municipalities: Affile, Jenne, Piglio, Roiate, Serrone, Subiaco, Trevi nel Lazio. It was called Ponza until 1891.

The area of Arcinazzo includes a wide plateau (altopiano in Italian), a popular holiday resort; the plateau is home to the remains of the Villa of Trajan, the summer palace and hunting residence of emperor Trajan.