Abstract: A gas bag for a vehicle occupant restraint system comprises a gas bag wall, which in the unfolded state of the gas bag (22) delimits an indentation (30) with an orifice (28) or an opening, and a closure piece (40) fastened to the gas bag wall, which in the inflated state moves in front of the orifice (28:) of the indentation or in front of the opening and covers it. The closure piece (40) is formed from at least two covering pieces, arranged one over the other, overlapping each other, which respectively have a margin section which is not fastened to the gas bag wall.