Saint Marcellus of Tangier or Saint Marcellus the Centurion was a Roman centurion who is today venerated as a martyr-saint in both the Eastern Orthodox and the Catholic Church. His feast day is celebrated on October 30.

In the Roman army during classical antiquity, a centurion, was a commander, nominally of a century, a military unit originally consisting of 100 legionaries. The size of the century changed over time, and from the first century BC through most of the imperial era was reduced to 80 men.