An airbag includes a rear panel, a front panel, and an extension panel. The rear panel has an inflation aperture for receiving an inflation gas. The front panel has at least one communication aperture, and the front panel is connected to the rear panel at a peripheral seam to define a primary inflatable portion having a central axis. The extension panel has an inner edge that is connected to the front panel at a location that is offset from the central axis of the primary inflatable portion and an outer edge that is connected to at least one of the front panel or the rear panel to define a secondary inflatable portion that is in communication with the primary inflatable portion through the at least one communication aperture. When inflated by the inflation gas, the secondary inflatable portion extends outward with respect to the front panel toward a vehicle occupant.