A gas shut-off valve for installation in gas meters, has a valve disk that can be moved in the longitudinal direction with respect to its valve seat. The movement is realized by a linear unit held in the longitudinal direction in a valve casing, which is actuated by an electric motor via reduction gearing. The valve seat has a lip seal (6). The electric motor is a small DC motor (11). The reduction gearing (13, 14, 15, 15', 16) and the linear unit, are installed in a panel (3) of the valve casing (1, 3, 4, 10). The linear unit is a rack-and-pinion gearing or a sliding-screw gearing, having an adjusting-nut element (17, 17') and an adjusting rod (18, 18').