A closure for a drinking bottle includes a closure cap for fixing the closure to a drinking bottle. The closure cap has a through hole and at least one ventilation opening, and a seal arranged in the closure cap. Either the seal or the closure cap has a web, by which the seal and the closure cap are at least in contact section-wise. The seal is of such a configuration that, upon the occurrence of an increased or reduced pressure in the bottle and/or by axial displacement of the seal in the closure cap, at least a section of the seal that is between the web and an inside wall of the closure cap lifts off the inside wall of the closure cap and thus opens a gap for ventilation of the drinking bottle by the at least one ventilation opening.