In the case of a trailer coupling for motor vehicles, including a cross member, which is connectable to a motor vehicle body, and a bearing unit, which carries a ball neck that at a first end is connected to the bearing unit and at a second end carries a coupling ball, and a holding base, which carries the bearing unit and is connected to the cross member, it is proposed according to the invention that the holding base should have a flange unit, for receiving the bearing unit, and two holding elements that project from the flange unit and in so doing run at a spacing from one another and act on the cross member.