The invention relates to an injection-molding tool (1) for plastics having a tool core (3, 5), an ejector (8) and a sliding tool portion (11) for forming an undercut, each of which is displaceable, the sliding tool portion (11) being displaceable both in the push-out direction (A) of the plastics molded component (4) produced in the tool and perpendicular to this direction, while the ejector and the tool core (3, 5) are displaceable in the ejection direction (A) and both the travel of the tool core (3, 5) and that of the sliding tool portion are derived from the travel of the ejector (8).