Shut-off valve for liquid or gaseous media including a valve housing having at least one passage opening connecting an inlet opening to an outlet opening, a valve seat arranged on the valve housing and surrounding the passage hole and can be closed by a valve closing element lying directly in contact, which are arranged in a control chamber formed in the valve housing between the inlet opening and the outlet opening, a drive, which can be connected to the valve housing and which actuates the valve closing element to open or close the passage hole, and a restoring element, which acts against a closing or opening motion of the valve closing element, wherein the drive has at least one setting element of a shape-memory alloy to actuate the opening or closing motion of the valve closing element, and the drive is separated from the control chamber by a sealing element.