Abstract: A self-retaining stopper for bottle containing pressurized contents such as champagne is disclosed. The stopper is especially adapted to cooperate with a bottle finish having a plurality of raised helical ribs of substantially uniform width and uniform maximum height spaced regularly around the circumference of the finish. The stopper comprises a shank for sealable insertion into the neck of such a bottle and a cup-shaped crown defining a resilient skirt overlying the finish. The skirt includes a plurality of inwardly projecting nodular protrusions for engaging the lower side of the helical ribs upon the inwardly directed urging of the resilient skirt. The inner wall of the skirt further includes a plurality of webs disposed to encounter the upper rim of the finish. The nodular protrusions and the webs are spaced apart a predetermined distance to secure the stopper in an axially locked position against the high pressures encountered within the bottle without the need for safety wiring or the like.