Loucetius was a Gallic god known from the Rhine-Moselle region, where he was identified with Mars.
Scholars have interpreted his name to mean ‘lightning’. Mars Loucetius was worshipped alongside the goddess Nemetona.
About a dozen inscriptions in honour of Mars Loucetius have been recovered, mainly from eastern Gaul, with a particular concentration among the Vangiones and Aresaces. Inscriptions to him have also been found at Bath and Angers; the altar at Bath specifies that it was dedicated by a citizen of the Treveri.