A vented protective cap for a liquid dispenser, and a venting insert, in particular for such a protective cap. The protective cap has a cap wall which surrounds a cap interior. The cap wall has a venting aperture which is spanned by a flexible sheet-like structure. A boundary region of the sheet-like structure is fixed in an encircling manner to a boundary of the venting aperture. The sheet-like structure consists of at least two layers which bear directly against one another but, at least in a central region of the sheet-like structure, are not connected fixedly to one another.