An airbag compising: a panel (110, 210, 310, 510, 610, 710, 810) defining at least a portion of an inflatable chamber (118, 518) that is configured to receive inflation gas from an inflator; a slit vent (120, 520, 620, 720, 820) comprising an elongated aperture (122, 222, 322, 422, 522, 622, 722, 822) that extends in a longitudinal direction from a first end to a second end and is at least partially defined by opposing first and second portions (176, 178; 276, 278; 576, 578; 676, 678; 776, 778; 876, 878) of the panel (110, 210, 310, 510, 610, 710, 810), wherein the slit vent (120, 520, 620, 720, 820) is configured to transition from a closed orientation to an open orientation, wherein the first and second portions (176, 178; 276, 278; 576, 578; 676, 678; 776, 778; 876, 878) of the panel (110, 210, 310, 510, 610, 710, 810) are approximated to each other in a transverse direction that is orthogonal to the longitudinal direction to inhibit venting of the inflatable chamber (118, 518) when the slit vent (120, 520, 620, 720, 820) is in the closed orientation, and wherein the opposing portions of the panel (110, 210, 310, 510, 610, 710, 810) are separated from each other in the transverse direction to permit venting of the inflatable chamber (118, 518) when the slit vent (120, 520, 620, 720, 820) is in the open orientation; characterized by: a first reinforcing seam (150, 250, 350, 450, 550) elongated in the longitudinal direction, wherein the first portion (176, 276, 576, 676, 776, 876) of the panel (110, 210, 310, 510, 610, 710, 810) comprises a portion of the first reinforcing seam (150, 250, 350, 450, 550) that borders the slit vent (120, 520, 620, 720, 820) from the first end to the second end of the slit vent (120, 520, 620, 720, 820); and a second reinforcing seam (160, 260, 360, 460, 560) elongated in the longitudinal direction, wherein the second portion (178, 278, 578, 678, 778, 878) of the panel (110, 210, 310, 510, 610, 710, 810) comprises a portion of the second reinforcing seam (160, 260, 360, 460, 560) that borders the slit vent (120, 520, 620, 720, 820) from the first end to the second end of the slit vent (120, 520, 620, 720, 820), wherein the first and second reinforcing seams (150, 160; 250, 260; 350, 360; 450, 460; 550, 560) cross one another at a position that is spaced in the longitudinal direction from the first end of the slit vent (120, 520, 620, 720, 820) and also cross one another at a position that is spaced in the longitudinal direction from the second end of the slit vent (120, 520, 620, 720, 820) to encompass the slit vent (120, 520, 620, 720, 820). a first reinforcing seam (150, 250, 350, 450, 550) elongated in the longitudinal direction, wherein the first portion (176, 276, 576, 676, 776, 876) of the panel (110, 210, 310, 510, 610, 710, 810) comprises a portion of the first reinforcing seam (150, 250, 350, 450, 550) that borders the slit vent (120, 520, 620, 720, 820) from the first end to the second end of the slit vent (120, 520, 620, 720, 820); and a second reinforcing seam (160, 260, 360, 460, 560) elongated in the longitudinal direction, wherein the second portion (178, 278, 578, 678, 778, 878) of the panel (110, 210, 310, 510, 610, 710, 810) comprises a portion of the second reinforcing seam (160, 260, 360, 460, 560) that borders the slit vent (120, 520, 620, 720, 820) from the first end to the second end of the slit vent (120, 520, 620, 720, 820), wherein the first and second reinforcing seams (150, 160; 250, 260; 350, 360; 450, 460; 550, 560) cross one another at a position that is spaced in the longitudinal direction from the first end of the slit vent (120, 520, 620, 720, 820) and also cross one another at a position that is spaced in the longitudinal direction from the second end of the slit vent (120, 520, 620, 720, 820) to encompass the slit vent (120, 520, 620, 720, 820).