A disinfecting cap is described including a housing, a protrusion and a cap cover, the housing including a top wall, an essentially cylindrical sidewall forming a first cavity, and an open bottom end opposite the top wall formed by the cylindrical sidewall with an opening to the first cavity within the housing for receiving a hub of a female needleless connector or a male needleless connector, wherein the protrusion is positioned within the first cavity and includes an inner surface, an outer surface and an end distal the top wall of the housing, the inner surface of the protrusion defining a second cavity, and wherein the outer surface of the protrusion and an inner surface of the essentially cylindrical sidewall define a gap therebetween, and the cap cover is dimensioned and positioned to cover at least a portion of the gap between the outer surface of the protrusion and the inner surface of the housing.