The so-called Temple of Diana is a 1st-century ancient Roman building in Nîmes, Gard, built under Augustus. It is located near the gushing spring of "La Fontaine", around which was an Augusteum, a sanctuary devoted to the cult of the emperor and his family, centred on a nymphaeum. Its basilica-like floor plan argues against it being a temple and there is no archaeological or literary evidence for its dedication to Diana.
The building may instead have been a library. Its facade was rebuilt during the 2nd century and in the mediaeval era it housed a monastery, ensuring its survival.
It was excavated in 1745 during work to create the garden of La Fontaine.
It was painted by Hubert Robert and other 18th century painters and was made a monument historique in 1840. It is now accessible from the jardins de la Fontaine.