Porza is first mentioned around 1297−99 as Porza.
1907-08 several cremation graves along with grave goods from the Iron Age were discovered. During the Middle Ages the Benedictine abbey of San Pietro in Ciel d'Oro owned land in Porza. On a hill northeast of Porza was Trevano castle, which was probably built in the 12th Century by the Bishop of Como. It was owned by the Brocchi family, from Como and later by the Trevano and Quadri families. On the castle's foundations a villa was built in 1871. During the Belle Époque the glamorous and wealthy met here, and musicians from across Europe presented themselves to give concerts. In 1934, the district purchased the villa. It was demolished in 1961 and replaced with a school, which is now part of the Scuola universitaria professionale della Svizzera italiana (university of Italian Switzerland).
Porza's church was under the parish church S. Lorenzo in Lugano until 1468, followed by the parish of Comano. It became an independent parish in 1647. The Church of SS. Bernardino e Martino dates from the 16th Century and was restored 1974.
Historically, the local economy relied on farming as well as craftsmen (Maestranze) emigrating to other countries. At the beginning of the 21st Century, it has become a residential community for the agglomeration of Lugano. Since the 1960s, a substantial proportion of the population comes from abroad or the rest of Switzerland. In the valley along the Cassarate river, an industrial and trade development zone has grown up. In 1992−95, a skating rink was built in Resega near the river. In 2000, about three-quarters of the workforce commutes.