Olloudius (Olludius, Ollodagus) is a Celtic god worshipped in Britain and Gaul. He is likely to have been considered a protector deity with wide-ranging influence.

He was sometimes identified by the Romans with their god Mars by way of the interpretatio romana.

Myth
Unknown.

Cult
Olloudius received votive and dedicatory offerings from his worshippers; otherwise little is known of the specifics of his cult.

Etymology
Olloudius’ name may have been derived from the Proto-Celtic *olyo or “all” and *dewo” or “god,” making him a god of all things.

Region
Olloudius was worshipped over a broad area, ranging from what is now Gloustershire, England to southern France.

Literary evidence
Unknown.

Archaeological evidence
Noville-lez-Bastogne, Belgium; Custom Scrubs, Bisley, England; Antibes, France; Ollioules, France; Vallauris, France