Dioscuri Temple, Roman temple in Naples, Italy

The Dioscuri Temple is a Roman sanctuary in Naples featuring a rectangular layout with columns and stone capitals that survive from antiquity. The structure displays the classical design principles Romans used in their sacred buildings, with decorative stone elements still visible in the remains.

The temple was probably first built at the founding of Neapolis, as foundations attributed to the 5th century BC suggest, and was dedicated to Castor and Pollux. It was rebuilt in the early imperial age, probably under Tiberius (AD 14-37), when the cult became dynastic; two imperial freedmen of eastern origin paid for the work. Between the 8th and 9th centuries it was absorbed into the church of San Paolo, keeping its facade, and the earthquakes of 1686-1688 brought down most of its columns.

Castor and Pollux were worshipped here as protectors of sailors and harbours, fitting for the port city of Neapolis, where they stood beside Apollo and Demeter. The temple faced the city's forum, the square later called Piazza San Gaetano, long a meeting point for traders passing through Naples.

The site sits next to San Paolo Maggiore Church and is best visited as part of a walking tour through Roman Naples. The remains are accessible from outside, though some portions lie beneath or integrated into the adjacent church and are better viewed from within.

The facade had eight Corinthian columns, each 13 metres tall; after the 1688 earthquake four stood, and two of those were later demolished. The two surviving columns now flank the main entrance of San Paolo Maggiore. Fragments of the statues of Castor and Pollux were recovered after the earthquake.