A Romano-Celtic temple or fanum is a sub-class of Roman temple found in the north-western Celtic provinces of the Roman Empire. They were the main places of worship in Gallo-Roman religion. Romano-Celtic temples differ from classical Roman temples, and evidence shows they had much continuity with earlier Celtic temples. Many were built on earlier sacred sites of the Celtic religion.

Ancient Roman temples were among the most important buildings in Roman culture, and some of the richest buildings in Roman architecture, though only a few survive in any sort of complete state. Today they remain "the most obvious symbol of Roman architecture". Their construction and maintenance was a major part of ancient Roman religion, and all towns of any importance had at least one main temple, as well as smaller shrines. The main room (cella) housed the cult image of the deity to whom the temple was dedicated, and often a table for supplementary offerings or libations and a small altar for incense. Behind the cella was a room, or rooms, used by temple attendants for storage of equipment and offerings. The ordinary worshiper rarely entered the cella, and most public ceremonies were performed outside of the cella where the sacrificial altar was located, on the portico, with a crowd gathered in the temple precinct.