Ambisagrus is a Celtic god worshipped in Gaul. His associations are uncertain given the single inscription on which his name appears.
He was sometimes identified by the Romans with their god Jupiter by way of the interpretatio romana; this connection, along with some interpretations of his name, has suggested to some that he may be a thunder god.
Ambisagrus received votive and dedicatory offerings from his worshippers; otherwise little is known of the specifics of his cult.
Ambisagrus’ name may have been derived from the Proto-Celtic *sagro- or “strong” and *ambi- which is a preposition meaning “around” or which can serve to strengthen the word it is attached to.
Ambisagrus is known from an inscription found at Aquileia in Cisalpine Gaul in what is now northern Italy.