A vehicle occupant protection system includes: a seat belt apparatus including a shoulder belt (11) and a lap belt (13); an upper air bag (27, 113); a lower air bag (29, 67, 73, 83); and an inflation limiting structure (37, 53, 55, 57, 75, 85) which is provided in the lower air bag and limits inflation of a part of the lower air bag in a vehicle back-and-forth direction when the lower air bag is inflated. When the vehicle collision is detected or predicted, the upper and lower air bags are inflated and vertically come into contact with each other. Further, an upper part (41, 71, 79, 91) of the inflated lower air bag positioned above the inflation limiting structure is pressed by the upper air bag and bends toward the front of the vehicle at the inflation limiting structure.