In order to provide, as straightforwardly as possible, a trailer coupling comprising a ball neck which can be moved between an operating position and a rest position and has a pivot-bearing body disposed at a first end and a coupling ball disposed at a second end, also comprising a vehicle-mounted pivot-bearing unit in which the pivot-bearing body is accommodated such that it can be pivoted about a pivot axis between the operating position and the rest position, and further comprising a rotation-blocking device having at least one rotation-blocking body, which can be moved in a guide direction with at least one component in the radial direction in relation to the pivot axis, it being possible for the rotation-blocking body to be engaged with, and disengaged from, a receiving space by movement in the guide direction, and having an actuating body which has a wedge surface running transversely to the guide direction, can be moved in an actuating direction and the movement of which in the actuating direction can move, and force, the at least one rotation-blocking body in the guide direction, it is proposed that the rotation-blocking device comprises at least two rotation-blocking bodies, and that the rotation-blocking bodies can be moved in the respective guide direction by a common actuating body.