A closing cap for a container, comprising a lateral wall extending around an axis and a transversal wall positioned at one end of the lateral wall, a separation line (5") being provided on the lateral wall to define: a retaining ring (301"), which is configured to remain anchored to a neck of the container and extends up to a free edge; a closing element removably engageable with the neck, so as to open or close the container; the separation line (5") extending around the axis and being circumferentially interrupted to leave the retaining ring (301") and the closing element joined; wherein the retaining ring (301") comprises: - a joining portion at which the retaining ring (301") is joined to the closing element; - a first connecting band, which extends from a first end zone of the joining portion, and a second connecting band, which extends from a second end zone of the joining portion, the second end zone being positioned circumferentially on the opposite side to the first end zone; - a tab (308"), interposed between the first connecting band and the second connecting band so that, when the closing element is in an open condition and the connecting bands (306, 307) keep the closing element connected to the retaining ring (301"), the tab (308") can rest on the neck; characterised in that the tab (308") comprises a pair of lateral edges (311") and a bottom edge (309"), the bottom edge (309") being aligned with a first free lower edge and a second free lower edge of the first connecting band and of the second connecting band; and wherein on the lateral wall there are - an incision line (7") which extends between the separation line (5") and the free edge of the retaining ring (301"), defines the bottom edge (309") of the tab (308"), the first free lower edge of the first connecting band and the second free lower edge of the second connecting band and is made by means of a break line of the lateral wall; - two cut lines (6") which define the respective lateral edges (311") of the tab (308") and are made by cut lines passing through an entire thickness of the lateral wall. - a joining portion at which the retaining ring (301") is joined to the closing element; - a first connecting band, which extends from a first end zone of the joining portion, and a second connecting band, which extends from a second end zone of the joining portion, the second end zone being positioned circumferentially on the opposite side to the first end zone; - a tab (308"), interposed between the first connecting band and the second connecting band so that, when the closing element is in an open condition and the connecting bands (306, 307) keep the closing element connected to the retaining ring (301"), the tab (308") can rest on the neck; characterised in that the tab (308") comprises a pair of lateral edges (311") and a bottom edge (309"), the bottom edge (309") being aligned with a first free lower edge and a second free lower edge of the first connecting band and of the second connecting band; and wherein on the lateral wall there are - an incision line (7") which extends between the separation line (5") and the free edge of the retaining ring (301"), defines the bottom edge (309") of the tab (308"), the first free lower edge of the first connecting band and the second free lower edge of the second connecting band and is made by means of a break line of the lateral wall; - two cut lines (6") which define the respective lateral edges (311") of the tab (308") and are made by cut lines passing through an entire thickness of the lateral wall.