Abstract: This invention relates to an antitheft collar for bottles, characterized in that it consists of two hinged half-rings that comprise additional removable locking means (12, 13) to ensure that the collar is locked around the neck of a bottle, whereby at least one (2) of half-rings (2, 3) comprises means (102, 142) for attaching a detectable device that is able to trigger a remote alarm, whereby the inside surface of each of the half-rings comprises a number of flanges (4) that are intended to come into contact and are deformed on the neck of the bottle when the collar is closed, whereby flanges (4) can be deformed so as to make it possible for the collar to fit bottle necks of various diameters.