Abstract: The invention relates to a trailer coupling for a motor vehicle, wherein the trailer coupling has a coupling arm, on the free end region of which a ball neck is formed, on which a coupling ball is arranged for attaching a trailer or coupling a load carrier to the motor vehicle. The coupling ball is spherical on the side thereof facing away from the ball neck and has a spherical segment plane on the side thereof facing the ball neck. Between the spherical segment plane and a portion of the ball neck which has a smaller outer circumference than the spherical segment plane there is arranged a throat portion having a transition contour extending in a concave manner between the ball neck and the spherical segment. The transition contour transitions with a coupling ball transition region into an external contour of the coupling ball, in particular into the spherical segment plane, and transitions with a ball neck transition region into an outer surface of the ball neck.