The patron saint of San Giovanni Gemini is Saint John the Baptist, celebrated on 24 June, with the mother church dedicated to him. The municipal territory, an enclave entirely surrounded by the municipality of Cammarata, originates in 1451, when Federico Abatellis, count of Cammarata, obtained from King Ferdinand the privilege of building on his fiefs; in 1507 the licentia populandi was granted, which the counts exercised on a flat spot near Cammarata, beyond the Turibolo river.
According to an explanation handed down by Father La Pilusa, the town's origin would be tied to a landslide around 1537, when an earthquake caused the hill on which Cammarata's castle stood to collapse: the castle was repaired, but the houses on the edge of the cliff crumbled, and the families who suffered the worst losses are said to have obtained the count's permission to build on the plain of San Giovanni. The town also hosts the historic Festa di Gesù Nazareno, held on the second Sunday of June around the Carro Trionfale.
