A twelve-sided polygon-shaped air bag comprised of fabric for use in vehicle restraint systems and method of manufacture is disclosed. The air bag is constructed from fabric panels in the shape of congruent, twelve-sided polygons, which may be regular dodecagons or dodecagons having alternating short and long sides. The individual panels may be in the form of a single dodecagon, or in the form of two abutting dodecagons. The use of dodecagon-shaped panels allows for economical fabric utilization and increased fabrication efficiency, compared with panels having a circular shape.