In 5th-4th century BCE the territory of Giugliano was settled by the Osci. According to a tradition, the city was founded by a group of colonists from Cuma in 421 BCE, who called it Lilianum ("Land of the lilies"). The city remained a small center until 1207, when Cuma was destroyed by the Neapolitans; some of the citizens from that town, including the clergy and the cathedral capitular, took shelter in Giugliano. The first documents mentioning a fief in Giugliano dates from 1270.
Church of the Annunziata, known from the 16th century. It is home to several canvasses by Neapolitan artists such as Massimo Stanzione and Carlo Sellitto. it has a nave with apse and transept; the pulpit is in Roccoco style, while the rest of the interior is decorated in Baroque style. Notable are also the large wooden organ (late 16th century), the Chapel of Madonna della Pace and early 16th Stories of the Virgin' in the left transept.
Church of Sant'Anna. Of the original building, existing in the 14th century, the bell tower remains. It houses 16th-century paintings by Fabrizio Santafede and Pietro Negroni.
Church of Madonna delle Grazie, with a 14th-century bell tower and a 16th-century portal. The interior has a 15th-century Gothic Incoronation of the Virgin and early 16th-century frescoes.